feat(lua): vim.text.indent()

Problem:
Indenting text is a common task in plugins/scripts for
presentation/formatting, yet vim has no way of doing it (especially
"dedent", and especially non-buffer text).

Solution:
Introduce `vim.text.indent()`. It sets the *exact* indentation because
that's a more difficult (and thus more useful) task than merely
"increasing the current indent" (which is somewhat easy with a `gsub()`
one-liner).

7 files changed, 184 insertions, 199 deletions

diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index 8155559d66..6610d25afb 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -2041,11 +2041,11 @@ describe('float window', function()
           [2:----------------------------------------]|*6
           [3:----------------------------------------]|
         ## grid 2
-            neeed some dummy                      |
-            background text                       |
-            to show the effect                    |
-            of color blending                     |
-            of border shadow                      |
+          neeed some dummy                        |
+          background text                         |
+          to show the effect                      |
+          of color blending                       |
+          of border shadow                        |
           ^                                        |
         ## grid 3
                                                   |
@@ -2065,11 +2065,11 @@ describe('float window', function()
         }}
       else
         screen:expect{grid=[[
-            neeed some dummy                      |
-            background text                       |
-            to {1: halloj! }{23:e}ffect                    |
-            of {1: BORDAA  }{24:n}ding                     |
-            of {23:b}{24:order sha}dow                      |
+          neeed some dummy                        |
+          background text                         |
+          to sh{1: halloj! }{23:f}ect                      |
+          of co{1: BORDAA  }{24:i}ng                       |
+          of bo{23:r}{24:der shado}w                        |
           ^                                        |
                                                   |
         ]]}
diff --git a/test/functional/ui/hlstate_spec.lua b/test/functional/ui/hlstate_spec.lua
index e10c79fa48..e5b0d29f95 100644
--- a/test/functional/ui/hlstate_spec.lua
+++ b/test/functional/ui/hlstate_spec.lua
@@ -502,9 +502,7 @@ describe('ext_hlstate detailed highlights', function()
     local num_lines = 500
     insert('first line\n')
     for _ = 1, num_lines do
-      insert([[
-        line
-      ]])
+      api.nvim_paste('  line\n', false, -1)
     end
     insert('last line')
 
diff --git a/test/functional/ui/inccommand_user_spec.lua b/test/functional/ui/inccommand_user_spec.lua
index 3eee9a6e07..5d604d22d7 100644
--- a/test/functional/ui/inccommand_user_spec.lua
+++ b/test/functional/ui/inccommand_user_spec.lua
@@ -281,14 +281,14 @@ describe("'inccommand' for user commands", function()
     ]])
     feed('<Esc>')
     screen:expect([[
-        text on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      text on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
       ^                                        |
       {1:~                                       }|*7
                                               |
@@ -301,14 +301,14 @@ describe("'inccommand' for user commands", function()
     command('set inccommand=nosplit')
     feed(':Replace text cats')
     screen:expect([[
-        {10:cats} on line 1                        |
-        more {10:cats} on line 2                   |
-        oh no, even more {10:cats}                 |
-        will the {10:cats} ever stop               |
-        oh well                               |
-        did the {10:cats} stop                     |
-        why won't it stop                     |
-        make the {10:cats} stop                    |
+      {10:cats} on line 1                          |
+      more {10:cats} on line 2                     |
+      oh no, even more {10:cats}                   |
+      will the {10:cats} ever stop                 |
+      oh well                                 |
+      did the {10:cats} stop                       |
+      why won't it stop                       |
+      make the {10:cats} stop                      |
                                               |
       {1:~                                       }|*7
       :Replace text cats^                      |
@@ -319,21 +319,21 @@ describe("'inccommand' for user commands", function()
     command('set inccommand=split')
     feed(':Replace text cats')
     screen:expect([[
-        {10:cats} on line 1                        |
-        more {10:cats} on line 2                   |
-        oh no, even more {10:cats}                 |
-        will the {10:cats} ever stop               |
-        oh well                               |
-        did the {10:cats} stop                     |
-        why won't it stop                     |
-        make the {10:cats} stop                    |
+      {10:cats} on line 1                          |
+      more {10:cats} on line 2                     |
+      oh no, even more {10:cats}                   |
+      will the {10:cats} ever stop                 |
+      oh well                                 |
+      did the {10:cats} stop                       |
+      why won't it stop                       |
+      make the {10:cats} stop                      |
                                               |
       {3:[No Name] [+]                           }|
-      |1|   {10:cats} on line 1                    |
-      |2|   more {10:cats} on line 2               |
-      |3|   oh no, even more {10:cats}             |
-      |4|   will the {10:cats} ever stop           |
-      |6|   did the {10:cats} stop                 |
+      |1| {10:cats} on line 1                      |
+      |2| more {10:cats} on line 2                 |
+      |3| oh no, even more {10:cats}               |
+      |4| will the {10:cats} ever stop             |
+      |6| did the {10:cats} stop                   |
       {2:[Preview]                               }|
       :Replace text cats^                      |
     ]])
@@ -343,14 +343,14 @@ describe("'inccommand' for user commands", function()
     command('set inccommand=split')
     feed(':Replace text cats<Esc>')
     screen:expect([[
-        text on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      text on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
       ^                                        |
       {1:~                                       }|*7
                                               |
@@ -361,14 +361,14 @@ describe("'inccommand' for user commands", function()
     command('set inccommand=split')
     feed(':Replace text cats<CR>')
     screen:expect([[
-        cats on line 1                        |
-        more cats on line 2                   |
-        oh no, even more cats                 |
-        will the cats ever stop               |
-        oh well                               |
-        did the cats stop                     |
-        why won't it stop                     |
-        make the cats stop                    |
+      cats on line 1                          |
+      more cats on line 2                     |
+      oh no, even more cats                   |
+      will the cats ever stop                 |
+      oh well                                 |
+      did the cats stop                       |
+      why won't it stop                       |
+      make the cats stop                      |
       ^                                        |
       {1:~                                       }|*7
       :Replace text cats                      |
@@ -379,14 +379,14 @@ describe("'inccommand' for user commands", function()
     command('set inccommand=split')
     feed('gg:.Replace text cats')
     screen:expect([[
-        {10:cats} on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      {10:cats} on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
                                               |
       {1:~                                       }|*7
       :.Replace text cats^                     |
@@ -432,14 +432,14 @@ describe("'inccommand' for user commands", function()
     ]])
     feed(':C')
     screen:expect([[
-      {10:  cats on line 1}                        |
-        more cats on line 2                   |
-        oh no, even more cats                 |
-        will the cats ever stop               |
-        oh well                               |
-        did the cats stop                     |
-        why won't it stop                     |
-        make the cats stop                    |
+      {10:cats on line 1}                          |
+      more cats on line 2                     |
+      oh no, even more cats                   |
+      will the cats ever stop                 |
+      oh well                                 |
+      did the cats stop                       |
+      why won't it stop                       |
+      make the cats stop                      |
                                               |
       {1:~                                       }|*7
       :C^                                      |
@@ -482,42 +482,42 @@ describe("'inccommand' for user commands", function()
     ]])
     feed(':Test a.a.a.a.')
     screen:expect([[
-        text on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      text on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
       a.a.a.a.                                |
       {1:~                                       }|*7
       :Test a.a.a.a.^                          |
     ]])
     feed('<C-V><Esc>u')
     screen:expect([[
-        text on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      text on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
       a.a.a.                                  |
       {1:~                                       }|*7
       :Test a.a.a.a.{18:^[}u^                       |
     ]])
     feed('<Esc>')
     screen:expect([[
-        text on line 1                        |
-        more text on line 2                   |
-        oh no, even more text                 |
-        will the text ever stop               |
-        oh well                               |
-        did the text stop                     |
-        why won't it stop                     |
-        make the text stop                    |
+      text on line 1                          |
+      more text on line 2                     |
+      oh no, even more text                   |
+      will the text ever stop                 |
+      oh well                                 |
+      did the text stop                       |
+      why won't it stop                       |
+      make the text stop                      |
       ^                                        |
       {1:~                                       }|*7
                                               |
@@ -572,12 +572,12 @@ describe("'inccommand' for user commands", function()
     screen:expect({
       grid = [[
         Preview                                 |
-          oh no, even more text                 |
-          will the text ever stop               |
-          oh well                               |
-          did the text stop                     |
-          why won't it stop                     |
-          make the text stop                    |
+        oh no, even more text                   |
+        will the text ever stop                 |
+        oh well                                 |
+        did the text stop                       |
+        why won't it stop                       |
+        make the text stop                      |
                                                 |
         {1:~                                       }|*8
         :Test barb^az                            |
@@ -611,9 +611,9 @@ describe("'inccommand' with multiple buffers", function()
     command('set inccommand=nosplit')
     feed(':Replace foo bar')
     screen:expect([[
-        bar baz {10:bar}       │  {10:bar} bar baz      |
-        baz {10:bar} bar       │  bar baz {10:bar}      |
-        {10:bar} bar baz       │  baz {10:bar} bar      |
+      bar baz {10:bar}         │{10:bar} bar baz        |
+      baz {10:bar} bar         │bar baz {10:bar}        |
+      {10:bar} bar baz         │baz {10:bar} bar        |
                           │                   |
       {1:~                   }│{1:~                  }|*11
       {3:[No Name] [+]        }{2:[No Name] [+]      }|
@@ -621,9 +621,9 @@ describe("'inccommand' with multiple buffers", function()
     ]])
     feed('<CR>')
     screen:expect([[
-        bar baz bar       │  bar bar baz      |
-        baz bar bar       │  bar baz bar      |
-        bar bar baz       │  baz bar bar      |
+      bar baz bar         │bar bar baz        |
+      baz bar bar         │bar baz bar        |
+      bar bar baz         │baz bar bar        |
       ^                    │                   |
       {1:~                   }│{1:~                  }|*11
       {3:[No Name] [+]        }{2:[No Name] [+]      }|
@@ -635,19 +635,19 @@ describe("'inccommand' with multiple buffers", function()
     command('set inccommand=split')
     feed(':Replace foo bar')
     screen:expect([[
-        bar baz {10:bar}       │  {10:bar} bar baz      |
-        baz {10:bar} bar       │  bar baz {10:bar}      |
-        {10:bar} bar baz       │  baz {10:bar} bar      |
+      bar baz {10:bar}         │{10:bar} bar baz        |
+      baz {10:bar} bar         │bar baz {10:bar}        |
+      {10:bar} bar baz         │baz {10:bar} bar        |
                           │                   |
       {3:[No Name] [+]        }{2:[No Name] [+]      }|
       Buffer #1:                              |
-      |1|   {10:bar} bar baz                       |
-      |2|   bar baz {10:bar}                       |
-      |3|   baz {10:bar} bar                       |
+      |1| {10:bar} bar baz                         |
+      |2| bar baz {10:bar}                         |
+      |3| baz {10:bar} bar                         |
       Buffer #2:                              |
-      |1|   bar baz {10:bar}                       |
-      |2|   baz {10:bar} bar                       |
-      |3|   {10:bar} bar baz                       |
+      |1| bar baz {10:bar}                         |
+      |2| baz {10:bar} bar                         |
+      |3| {10:bar} bar baz                         |
                                               |
       {1:~                                       }|
       {2:[Preview]                               }|
@@ -655,9 +655,9 @@ describe("'inccommand' with multiple buffers", function()
     ]])
     feed('<CR>')
     screen:expect([[
-        bar baz bar       │  bar bar baz      |
-        baz bar bar       │  bar baz bar      |
-        bar bar baz       │  baz bar bar      |
+      bar baz bar         │bar bar baz        |
+      baz bar bar         │bar baz bar        |
+      bar bar baz         │baz bar bar        |
       ^                    │                   |
       {1:~                   }│{1:~                  }|*11
       {3:[No Name] [+]        }{2:[No Name] [+]      }|
diff --git a/test/functional/ui/linematch_spec.lua b/test/functional/ui/linematch_spec.lua
index 3593604c49..dc16036f21 100644
--- a/test/functional/ui/linematch_spec.lua
+++ b/test/functional/ui/linematch_spec.lua
@@ -95,8 +95,7 @@ describe('Diff mode screen with 3 diffs open', function()
       {7:  }{8:  9 }{4:    BBB                    }│{7:  }{8:  9 }{4:    BBB                   }│{7:  }{8:    }{23:---------------------------}|
       {7:  }{8: 10 }{4:    BBB                    }│{7:  }{8: 10 }{4:    BBB                   }│{7:  }{8:    }{23:---------------------------}|
       {7:  }{8: 11 }{4:>>>>>>> branch1            }│{7:  }{8: 11 }{4:>>>>>>> branch1           }│{7:  }{8:    }{23:---------------------------}|
-      {7:  }{8: 12 }                           │{7:  }{8: 12 }                          │{7:  }{8:  6 }                           |
-      {1:~                                }│{1:~                               }│{1:~                                }|*2
+      {1:~                                }│{1:~                               }│{1:~                                }|*3
       {3:<-functional-diff-screen-1.3 [+]  }{2:<est-functional-diff-screen-1.2  Xtest-functional-diff-screen-1   }|
       :2,6diffget screen-1.2                                                                              |
       ]])
@@ -114,8 +113,7 @@ describe('Diff mode screen with 3 diffs open', function()
       {7:  }{8:  4 }{4:    }{27:BBB}{4:                    }│{7:  }{8:  6 }{4:    }{27:BBB}{4:                   }│{7:  }{8:  4 }{4:    }{27:AAA}{4:                    }|
       {7:  }{8:  5 }{4:    }{27:BBB}{4:                    }│{7:  }{8:  7 }{4:    }{27:BBB}{4:                   }│{7:  }{8:  5 }{4:    }{27:AAA}{4:                    }|
       {7:  }{8:    }{23:---------------------------}│{7:  }{8:  8 }{22:>>>>>>> branch1           }│{7:  }{8:    }{23:---------------------------}|
-      {7:  }{8:  6 }                           │{7:  }{8:  9 }                          │{7:  }{8:  6 }                           |
-      {1:~                                }│{1:~                               }│{1:~                                }|*5
+      {1:~                                }│{1:~                               }│{1:~                                }|*6
       {2:<test-functional-diff-screen-1.3  }{3:<functional-diff-screen-1.2 [+]  }{2:Xtest-functional-diff-screen-1   }|
       :5,7diffget screen-1.3                                                                              |
       ]])
@@ -136,8 +134,7 @@ describe('Diff mode screen with 3 diffs open', function()
       {7:  }{8:  4 }    BBB                    │{7:  }{8:  9 }    BBB                   │{7:  }{8:  8 }    BBB                    |
       {7:  }{8:  5 }    BBB                    │{7:  }{8: 10 }    BBB                   │{7:  }{8:  9 }    BBB                    |
       {7:  }{8:    }{23:---------------------------}│{7:  }{8: 11 }{4:>>>>>>> branch1           }│{7:  }{8: 10 }{4:>>>>>>> branch1            }|
-      {7:  }{8:  6 }                           │{7:  }{8: 12 }                          │{7:  }{8: 11 }                           |
-      {1:~                                }│{1:~                               }│{1:~                                }|*2
+      {1:~                                }│{1:~                               }│{1:~                                }|*3
       {2:<test-functional-diff-screen-1.3  <est-functional-diff-screen-1.2  }{3:<st-functional-diff-screen-1 [+] }|
       :5,6diffget screen-1.2                                                                              |
       ]])
@@ -158,8 +155,7 @@ describe('Diff mode screen with 3 diffs open', function()
       {7:  }{8:  4 }{4:    BBB                    }│{7:  }{8:  9 }{4:    BBB                   }│{7:  }{8:    }{23:---------------------------}|
       {7:  }{8:  5 }    BBB                    │{7:  }{8: 10 }    BBB                   │{7:  }{8:  7 }    BBB                    |
       {7:  }{8:    }{23:---------------------------}│{7:  }{8: 11 }{22:>>>>>>> branch1           }│{7:  }{8:    }{23:---------------------------}|
-      {7:  }{8:  6 }                           │{7:  }{8: 12 }                          │{7:  }{8:  8 }                           |
-      {1:~                                }│{1:~                               }│{1:~                                }|*2
+      {1:~                                }│{1:~                               }│{1:~                                }|*3
       {2:<test-functional-diff-screen-1.3  }{3:<est-functional-diff-screen-1.2  }{2:<st-functional-diff-screen-1 [+] }|
       :6,8diffput screen-1                                                                                |
       ]])
@@ -179,8 +175,7 @@ describe('Diff mode screen with 3 diffs open', function()
       {7:  }{8:  4 }    BBB                    │{7:  }{8:  9 }    BBB                   │{7:  }{8:  8 }    BBB                    |
       {7:  }{8:  5 }    BBB                    │{7:  }{8: 10 }    BBB                   │{7:  }{8:  9 }    BBB                    |
       {7:  }{8:    }{23:---------------------------}│{7:  }{8: 11 }{4:>>>>>>> branch1           }│{7:  }{8: 10 }{4:>>>>>>> branch1            }|
-      {7:  }{8:  6 }                           │{7:  }{8: 12 }                          │{7:  }{8: 11 }                           |
-      {1:~                                }│{1:~                               }│{1:~                                }|*2
+      {1:~                                }│{1:~                               }│{1:~                                }|*3
       {2:<test-functional-diff-screen-1.3  }{3:<est-functional-diff-screen-1.2  }{2:<st-functional-diff-screen-1 [+] }|
       :6,11diffput screen-1                                                                               |
       ]])
@@ -276,8 +271,7 @@ something
       {7:  }{8: 14 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 15 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 16 }                                           │{7:  }{8: 18 }                                            |
-      {1:~                                                }│{1:~                                                 }|*6
+      {1:~                                                }│{1:~                                                 }|*7
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :5,9diffget                                                                                         |
       ]])
@@ -300,8 +294,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 12 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 13 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 14 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 15 }                                            |
-      {1:~                                                }│{1:~                                                 }|*3
+      {1:~                                                }│{1:~                                                 }|*4
       {2:Xtest-functional-diff-screen-1.2                  }{3:Xtest-functional-diff-screen-1 [+]                }|
       :5,10diffget                                                                                        |
       ]])
@@ -322,8 +315,7 @@ something
       {7:  }{8: 10 }common line                                │{7:  }{8: 10 }common line                                 |
       {7:  }{8: 11 }common line                                │{7:  }{8: 11 }common line                                 |
       {7:  }{8: 12 }something                                  │{7:  }{8: 12 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 13 }                                            |
-      {1:~                                                }│{1:~                                                 }|*5
+      {1:~                                                }│{1:~                                                 }|*6
       {2:Xtest-functional-diff-screen-1.2                  }{3:Xtest-functional-diff-screen-1 [+]                }|
       :4,17diffget                                                                                        |
       ]])
@@ -349,7 +341,7 @@ something
       {7:  }{8: 15 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8: 16 }DEF                                        │{7:  }{8: 16 }DEF                                         |
       {7:  }{8: 17 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 18 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :4,12diffget                                                                                        |
       ]])
@@ -376,7 +368,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -403,7 +395,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -430,7 +422,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -457,7 +449,7 @@ something
       {7:  }{8: 12 }^common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 13 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 14 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -484,7 +476,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8: 12 }DEF                                        │{7:  }{8: 16 }DEF                                         |
       {7:  }{8: 13 }^something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 14 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -511,7 +503,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1 [+]                }|
       :e                                                                                                  |
       ]])
@@ -538,7 +530,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1 [+]                }|
       :e                                                                                                  |
       ]])
@@ -565,7 +557,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1 [+]                }|
       :e                                                                                                  |
       ]])
@@ -591,7 +583,7 @@ something
       {7:  }{8: 11 }^common line                                │{7:  }{8: 14 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 15 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 16 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 17 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1 [+]                }|
       :e                                                                                                  |
@@ -618,7 +610,7 @@ something
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 14 }{22:DEF                                         }|
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8: 12 }^something                                  │{7:  }{8: 16 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 17 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {1:~                                                }│{1:~                                                 }|
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1 [+]                }|
       :e                                                                                                  |
@@ -646,7 +638,7 @@ something
       {7:  }{8: 14 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 15 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 16 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {2:Xtest-functional-diff-screen-1.2 [+]              }{3:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -673,7 +665,7 @@ something
       {7:  }{8: 14 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 15 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 16 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {2:Xtest-functional-diff-screen-1.2 [+]              }{3:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -700,7 +692,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8: 16 }{22:DEF                                         }|
       {7:  }{8: 12 }something                                  │{7:  }{8: 17 }something                                   |
-      {7:  }{8: 13 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {2:Xtest-functional-diff-screen-1.2 [+]              }{3:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -727,7 +719,7 @@ something
       {7:  }{8: 11 }common line                                │{7:  }{8: 15 }common line                                 |
       {7:  }{8: 12 }DEF                                        │{7:  }{8: 16 }DEF                                         |
       {7:  }{8: 13 }something                                  │{7:  }{8: 17 }^something                                   |
-      {7:  }{8: 14 }                                           │{7:  }{8: 18 }                                            |
+      {1:~                                                }│{1:~                                                 }|
       {2:Xtest-functional-diff-screen-1.2 [+]              }{3:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -757,8 +749,7 @@ d
       {7:  }{8:  2 }{4:abc d                                      }│{7:  }{8:  1 }{27:// }{4:abc d                                    }|
       {7:  }{8:  3 }{4:d                                          }│{7:  }{8:  2 }{27:// }{4:d                                        }|
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8:  3 }{22:// d                                        }|
-      {7:  }{8:  4 }                                           │{7:  }{8:  4 }                                            |
-      {1:~                                                }│{1:~                                                 }|*13
+      {1:~                                                }│{1:~                                                 }|*14
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -794,8 +785,7 @@ void testFunction () {
       {7:  }{8:  3 }{4:  }{27:// }{4:}                                     }│{7:  }{8:  4 }{4:    }                                       }|
       {7:  }{8:    }{23:-------------------------------------------}│{7:  }{8:  5 }{22:  }                                         }|
       {7:  }{8:  4 }}                                          │{7:  }{8:  6 }}                                           |
-      {7:  }{8:  5 }                                           │{7:  }{8:  7 }                                            |
-      {1:~                                                }│{1:~                                                 }|*11
+      {1:~                                                }│{1:~                                                 }|*12
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -834,8 +824,7 @@ void testFunction () {
       {7:  }{8:  6 }{22:?B                                         }│{7:  }{8:    }{23:--------------------------------------------}|
       {7:  }{8:  7 }{22:?B                                         }│{7:  }{8:    }{23:--------------------------------------------}|
       {7:  }{8:  8 }{22:?C                                         }│{7:  }{8:    }{23:--------------------------------------------}|
-      {7:  }{8:  9 }                                           │{7:  }{8:  4 }                                            |
-      {1:~                                                }│{1:~                                                 }|*9
+      {1:~                                                }│{1:~                                                 }|*10
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -874,8 +863,7 @@ void testFunction () {
       {7:  }{8:  6 }{27:?}{4:B                                         }│{7:  }{8:  2 }{27:!}{4:B                                          }|
       {7:  }{8:  7 }{27:?}{4:C                                         }│{7:  }{8:  3 }{27:!}{4:C                                          }|
       {7:  }{8:  8 }{22:?C                                         }│{7:  }{8:    }{23:--------------------------------------------}|
-      {7:  }{8:  9 }                                           │{7:  }{8:  4 }                                            |
-      {1:~                                                }│{1:~                                                 }|*9
+      {1:~                                                }│{1:~                                                 }|*10
       {3:Xtest-functional-diff-screen-1.2                  }{2:Xtest-functional-diff-screen-1                    }|
       :e                                                                                                  |
       ]])
@@ -1017,8 +1005,7 @@ something
       {7:  }{8:  9 }HIL                                        │{7:  }{8:  9 }HIL                                         |
       {7:  }{8: 10 }common line                                │{7:  }{8: 10 }common line                                 |
       {7:  }{8: 11 }something                                  │{7:  }{8: 11 }something                                   |
-      {7:  }{8: 12 }                                           │{7:  }{8: 12 }                                            |
-      {1:~                                                }│{1:~                                                 }|*6
+      {1:~                                                }│{1:~                                                 }|*7
       {3:Xtest-functional-diff-screen-1.2 [+]              }{2:Xtest-functional-diff-screen-1                    }|
       :1,19diffget                                                                                        |
       ]])
diff --git a/test/functional/ui/popupmenu_spec.lua b/test/functional/ui/popupmenu_spec.lua
index fe093b67d5..375bc560dc 100644
--- a/test/functional/ui/popupmenu_spec.lua
+++ b/test/functional/ui/popupmenu_spec.lua
@@ -2318,25 +2318,26 @@ describe('builtin popupmenu', function()
         command('set completeopt+=noinsert')
         command('set mouse=a')
         insert([[
-          Lorem ipsum dolor sit amet, consectetur
-          adipisicing elit, sed do eiusmod tempor
-          incididunt ut labore et dolore magna aliqua.
-          Ut enim ad minim veniam, quis nostrud
-          exercitation ullamco laboris nisi ut aliquip ex
-          ea commodo consequat. Duis aute irure dolor in
-          reprehenderit in voluptate velit esse cillum
-          dolore eu fugiat nulla pariatur. Excepteur sint
-          occaecat cupidatat non proident, sunt in culpa
-          qui officia deserunt mollit anim id est
-          laborum.
+            Lorem ipsum dolor sit amet, consectetur
+            adipisicing elit, sed do eiusmod tempor
+            incididunt ut labore et dolore magna aliqua.
+            Ut enim ad minim veniam, quis nostrud
+            exercitation ullamco laboris nisi ut aliquip ex
+            ea commodo consequat. Duis aute irure dolor in
+            reprehenderit in voluptate velit esse cillum
+            dolore eu fugiat nulla pariatur. Excepteur sint
+            occaecat cupidatat non proident, sunt in culpa
+            qui officia deserunt mollit anim id est
+            laborum.
+          .
         ]])
 
         screen:expect([[
-            reprehenderit in voluptate velit esse cillum              |
             dolore eu fugiat nulla pariatur. Excepteur sint           |
             occaecat cupidatat non proident, sunt in culpa            |
             qui officia deserunt mollit anim id est                   |
             laborum.                                                  |
+          .                                                           |
           ^                                                            |
           {4:[No Name] [+]                                               }|
             Lorem ipsum dolor sit amet, consectetur                   |
diff --git a/test/functional/ui/screen.lua b/test/functional/ui/screen.lua
index 934b4e9032..adc3080586 100644
--- a/test/functional/ui/screen.lua
+++ b/test/functional/ui/screen.lua
@@ -494,9 +494,8 @@ function Screen:expect(expected, attr_ids, ...)
 
   local expected_rows = {} --- @type string[]
   if grid then
-    -- Remove the last line and dedent. Note that gsub returns more then one
-    -- value.
-    grid = dedent(grid:gsub('\n[ ]+$', ''), 0)
+    -- Dedent (ignores last line if it is blank).
+    grid = dedent(grid, 0)
     for row in grid:gmatch('[^\n]+') do
       table.insert(expected_rows, row)
     end
diff --git a/test/functional/ui/searchhl_spec.lua b/test/functional/ui/searchhl_spec.lua
index 86490b4527..5479cf6ee6 100644
--- a/test/functional/ui/searchhl_spec.lua
+++ b/test/functional/ui/searchhl_spec.lua
@@ -73,10 +73,10 @@ describe('search highlighting', function()
     -- 'hlsearch' is enabled by default. #2859
     feed('gg/text<cr>')
     screen:expect([[
-        some {2:^text}                             |
-        more {2:text}stuff                        |
-        stupid{2:texttext}stuff                   |
-        a {2:text} word                           |
+      some {2:^text}                               |
+      more {2:text}stuff                          |
+      stupid{2:texttext}stuff                     |
+      a {2:text} word                             |
                                               |
       {1:~                                       }|
       /text                                   |
@@ -85,10 +85,10 @@ describe('search highlighting', function()
     -- overlapping matches not allowed
     feed('3nx')
     screen:expect([[
-        some {2:text}                             |
-        more {2:text}stuff                        |
-        stupid{2:text}^extstuff                    |
-        a {2:text} word                           |
+      some {2:text}                               |
+      more {2:text}stuff                          |
+      stupid{2:text}^extstuff                      |
+      a {2:text} word                             |
                                               |
       {1:~                                       }|
       /text                                   |
@@ -96,10 +96,10 @@ describe('search highlighting', function()
 
     feed('ggn*') -- search for entire word
     screen:expect([[
-        some {2:text}                             |
-        more textstuff                        |
-        stupidtextextstuff                    |
-        a {2:^text} word                           |
+      some {2:text}                               |
+      more textstuff                          |
+      stupidtextextstuff                      |
+      a {2:^text} word                             |
                                               |
       {1:~                                       }|
       /\<text\>                               |
@@ -107,10 +107,10 @@ describe('search highlighting', function()
 
     feed_command('nohlsearch')
     screen:expect([[
-        some text                             |
-        more textstuff                        |
-        stupidtextextstuff                    |
-        a ^text word                           |
+      some text                               |
+      more textstuff                          |
+      stupidtextextstuff                      |
+      a ^text word                             |
                                               |
       {1:~                                       }|
       :nohlsearch                             |
@@ -641,7 +641,7 @@ describe('search highlighting', function()
     feed_command('/ial te')
     screen:expect {
       grid = [[
-        very {5:spec^ial}{2: te}{6:xt}                     |
+      very {5:spec^ial}{2: te}{6:xt}                       |
                                               |
       {1:~                                       }|*4
       {4:search hit BOTTOM, continuing at TOP}    |
@@ -652,7 +652,7 @@ describe('search highlighting', function()
           topline = 0,
           botline = 3,
           curline = 0,
-          curcol = 11,
+          curcol = 9,
           linecount = 2,
           sum_scroll_delta = 0,
         },
@@ -670,7 +670,7 @@ describe('search highlighting', function()
     }
     command('%foldopen')
     screen:expect([[
-        very {5:spec^ial}{2: te}{6:xt}                     |
+      very {5:spec^ial}{2: te}{6:xt}                       |
                                               |
       {1:~                                       }|*4
       {4:search hit BOTTOM, continuing at TOP}    |
@@ -678,7 +678,7 @@ describe('search highlighting', function()
 
     feed_command('call clearmatches()')
     screen:expect([[
-        very spec{2:^ial te}xt                     |
+      very spec{2:^ial te}xt                       |
                                               |
       {1:~                                       }|*4
       :call clearmatches()                    |
@@ -688,7 +688,7 @@ describe('search highlighting', function()
     -- nonconflicting attributes are combined
     feed_command('syntax keyword MyGroup special')
     screen:expect([[
-        very {5:spec}{7:^ial}{2: te}xt                     |
+      very {5:spec}{7:^ial}{2: te}xt                       |
                                               |
       {1:~                                       }|*4
       :syntax keyword MyGroup special         |