vim-patch:9.1.0917: various vartabstop and shiftround bugs when shifting lines

Problem:  various vartabstop and shiftround bugs when shifting lines
Solution: Fix the bugs, add new tests for shifting lines in various ways
          (Gary Johnson)

fixes: vim/vim#14891
closes: vim/vim#16193

https://github.com/vim/vim/commit/eed63f96d26723ff31a9728647eed526d06a553d

Co-authored-by: Gary Johnson <garyjohn@spocom.com>

2 files changed, 931 insertions, 17 deletions

diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 9524c67301..71a005bd24 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -274,21 +274,53 @@ void op_shift(oparg_T *oap, bool curs_top, int amount)
   changed_lines(curbuf, oap->start.lnum, 0, oap->end.lnum + 1, 0, true);
 }
 
-/// Shift the current line one shiftwidth left (if left != 0) or right
-/// leaves cursor on first blank in the line.
-///
-/// @param call_changed_bytes  call changed_bytes()
-void shift_line(bool left, bool round, int amount, int call_changed_bytes)
+/// Return the tabstop width at the index of the variable tabstop array.  If an
+/// index greater than the length of the array is given, the last tabstop width
+/// in the array is returned.
+static int get_vts(const int *vts_array, int index)
+{
+  int ts;
+
+  if (index < 1) {
+    ts = 0;
+  } else if (index <= vts_array[0]) {
+    ts = vts_array[index];
+  } else {
+    ts = vts_array[vts_array[0]];
+  }
+
+  return ts;
+}
+
+/// Return the sum of all the tabstops through the index-th.
+static int get_vts_sum(const int *vts_array, int index)
 {
-  int sw_val = get_sw_value_indent(curbuf, left);
-  if (sw_val == 0) {
-    sw_val = 1;              // shouldn't happen, just in case
+  int sum = 0;
+  int i;
+
+  // Perform the summation for indeces within the actual array.
+  for (i = 1; i <= index && i <= vts_array[0]; i++) {
+    sum += vts_array[i];
   }
+
+  // Add topstops whose indeces exceed the actual array.
+  if (i <= index) {
+    sum += vts_array[vts_array[0]] * (index - vts_array[0]);
+  }
+
+  return sum;
+}
+
+/// @param left    true if shift is to the left
+/// @param count   true if new indent is to be to a tabstop
+/// @param amount  number of shifts
+static int64_t get_new_sw_indent(bool left, bool round, int64_t amount, int64_t sw_val)
+{
   int64_t count = get_indent();  // get current indent
 
   if (round) {  // round off indent
-    int i = trim_to_int(count / sw_val);  // number of 'shiftwidth' rounded down
-    int j = trim_to_int(count % sw_val);  // extra spaces
+    int64_t i = trim_to_int(count / sw_val);  // number of 'shiftwidth' rounded down
+    int64_t j = trim_to_int(count % sw_val);  // extra spaces
     if (j && left) {  // first remove extra spaces
       amount--;
     }
@@ -297,15 +329,98 @@ void shift_line(bool left, bool round, int amount, int call_changed_bytes)
     } else {
       i += amount;
     }
-    count = (int64_t)i * (int64_t)sw_val;
+    count = i * sw_val;
   } else {  // original vi indent
     if (left) {
-      count = MAX(count - (int64_t)sw_val * (int64_t)amount, 0);
+      count = MAX(count - sw_val * amount, 0);
+    } else {
+      count += sw_val * amount;
+    }
+  }
+
+  return count;
+}
+
+/// @param left    true if shift is to the left
+/// @param count   true if new indent is to be to a tabstop
+/// @param amount  number of shifts
+static int64_t get_new_vts_indent(bool left, bool round, int amount, int *vts_array)
+{
+  int64_t indent = get_indent();
+  int vtsi = 0;
+  int vts_indent = 0;
+  int ts = 0;         // Silence uninitialized variable warning.
+
+  // Find the tabstop at or to the left of the current indent.
+  while (vts_indent <= indent) {
+    vtsi++;
+    ts = get_vts(vts_array, vtsi);
+    vts_indent += ts;
+  }
+  vts_indent -= ts;
+  vtsi--;
+
+  // Extra indent spaces to the right of the tabstop
+  int64_t offset = indent - vts_indent;
+
+  if (round) {
+    if (left) {
+      if (offset == 0) {
+        indent = get_vts_sum(vts_array, vtsi - amount);
+      } else {
+        indent = get_vts_sum(vts_array, vtsi - (amount - 1));
+      }
+    } else {
+      indent = get_vts_sum(vts_array, vtsi + amount);
+    }
+  } else {
+    if (left) {
+      if (amount > vtsi) {
+        indent = 0;
+      } else {
+        indent = get_vts_sum(vts_array, vtsi - amount) + offset;
+      }
     } else {
-      count += (int64_t)sw_val * (int64_t)amount;
+      indent = get_vts_sum(vts_array, vtsi + amount) + offset;
     }
   }
 
+  return indent;
+}
+
+/// Shift the current line 'amount' shiftwidth(s) left (if 'left' is true) or
+/// right.
+///
+/// The rules for choosing a shiftwidth are:  If 'shiftwidth' is non-zero, use
+/// 'shiftwidth'; else if 'vartabstop' is not empty, use 'vartabstop'; else use
+/// 'tabstop'.  The Vim documentation says nothing about 'softtabstop' or
+/// 'varsofttabstop' affecting the shiftwidth, and neither affects the
+/// shiftwidth in current versions of Vim, so they are not considered here.
+///
+/// @param left                true if shift is to the left
+/// @param count               true if new indent is to be to a tabstop
+/// @param amount              number of shifts
+/// @param call_changed_bytes  call changed_bytes()
+void shift_line(bool left, bool round, int amount, int call_changed_bytes)
+{
+  int64_t count;
+  int64_t sw_val = curbuf->b_p_sw;
+  int64_t ts_val = curbuf->b_p_ts;
+  int *vts_array = curbuf->b_p_vts_array;
+
+  if (sw_val != 0) {
+    // 'shiftwidth' is not zero; use it as the shift size.
+    count = get_new_sw_indent(left, round, amount, sw_val);
+  } else if ((vts_array == NULL) || (vts_array[0] == 0)) {
+    // 'shiftwidth' is zero and 'vartabstop' is empty; use 'tabstop' as the
+    // shift size.
+    count = get_new_sw_indent(left, round, amount, ts_val);
+  } else {
+    // 'shiftwidth' is zero and 'vartabstop' is defined; use 'vartabstop'
+    // to determine the new indent.
+    count = get_new_vts_indent(left, round, amount, vts_array);
+  }
+
   // Set new indent
   if (State & VREPLACE_FLAG) {
     change_indent(INDENT_SET, trim_to_int(count), false, call_changed_bytes);
diff --git a/test/old/testdir/test_shift.vim b/test/old/testdir/test_shift.vim
index ec357dac88..f31c5a11e6 100644
--- a/test/old/testdir/test_shift.vim
+++ b/test/old/testdir/test_shift.vim
@@ -108,10 +108,809 @@ func Test_ex_shift_errors()
   call assert_fails('>!', 'E477:')
   call assert_fails('<!', 'E477:')
 
-  " call assert_fails('2,1>', 'E493:')
-  call assert_fails('execute "2,1>"', 'E493:')
-  " call assert_fails('2,1<', 'E493:')
-  call assert_fails('execute "2,1<"', 'E493:')
+  call assert_fails('2,1>', 'E493:')
+  call assert_fails('2,1<', 'E493:')
+endfunc
+
+" Test inserting a backspace at the start of a line.
+"
+" This is to verify the proper behavior of tabstop_start() as called from
+" ins_bs().
+"
+func Test_shift_ins_bs()
+  set backspace=indent,start
+  set softtabstop=11
+
+  call setline(1, repeat(" ", 33) . "word")
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 22) . "word", getline(1))
+  call setline(1, repeat(" ", 23) . "word")
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 22) . "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 11) . "word", getline(1))
+
+  set backspace& softtabstop&
+  bw!
+endfunc
+
+" Test inserting a backspace at the start of a line, with 'varsofttabstop'.
+"
+func Test_shift_ins_bs_vartabs()
+  CheckFeature vartabs
+  set backspace=indent,start
+  set varsofttabstop=13,11,7
+
+  call setline(1, repeat(" ", 44) . "word")
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 38) . "word", getline(1))
+  call setline(1, repeat(" ", 39) . "word")
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 38) . "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 31) . "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 24) . "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(repeat(" ", 13) . "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(                  "word", getline(1))
+  exe "norm! I\<BS>"
+  call assert_equal(                  "word", getline(1))
+
+  set backspace& varsofttabstop&
+  bw!
+endfunc
+
+" Test the >> and << normal-mode commands.
+"
+func Test_shift_norm()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "  word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  norm! >>
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  12) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  17) . "word", getline(1))
+
+  norm! <<
+  call assert_equal(repeat(" ",  12) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "  word")
+
+  norm! >>
+  call assert_equal(repeat(" ",  9) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  16) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  23) . "word", getline(1))
+
+  norm! <<
+  call assert_equal(repeat(" ",  16) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  9) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the >> and << normal-mode commands, with 'vartabstop'.
+"
+func Test_shift_norm_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "  word")
+
+  norm! >>
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  38) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  49) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  60) . "word", getline(1))
+
+  norm! <<
+  call assert_equal(repeat(" ",  49) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  38) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test the >> and << normal-mode commands with 'shiftround'.
+"
+func Test_shift_norm_round()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  5) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  10) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  15) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  20) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  25) . "word", getline(1))
+
+  norm! <<
+  call assert_equal(repeat(" ",  20) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  15) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  10) . "word", getline(1))
+  exe "norm! I  "
+  norm! <<
+  call assert_equal(repeat(" ",  10) . "word", getline(1))
+
+  call setline(1, repeat(" ", 7) . "word")
+  norm! <<
+  call assert_equal(repeat(" ",  5) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  call setline(1, repeat(" ", 2) . "word")
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "word")
+
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  14) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  28) . "word", getline(1))
+  norm! >>
+  call assert_equal(repeat(" ",  35) . "word", getline(1))
+
+  norm! <<
+  call assert_equal(repeat(" ",  28) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  14) . "word", getline(1))
+  exe "norm! I  "
+  norm! <<
+  call assert_equal(repeat(" ",  14) . "word", getline(1))
+
+  call setline(1, repeat(" ", 9) . "word")
+  norm! <<
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  call setline(1, repeat(" ", 2) . "word")
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftround& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the >> and << normal-mode commands with 'shiftround' and 'vartabstop'.
+"
+func Test_shift_norm_round_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "word")
+
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  36) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  47) . "word", getline(1))
+  exe "norm! I  "
+  norm! >>
+  call assert_equal(repeat(" ",  58) . "word", getline(1))
+
+  exe "norm! I  "
+  norm! <<
+  call assert_equal(repeat(" ",  58) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  47) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  36) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  norm! <<
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  exe "norm! I  "
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftround& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test the V> and V< visual-mode commands.
+"
+" See ":help v_<" and ":help v_>".  See also the last paragraph of "3. Simple
+" changes", ":help simple-change", immediately above "4. Complex changes",
+" ":help complex-change".
+"
+func Test_shift_vis()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "  word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  norm! V>
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  norm! V2>
+  call assert_equal(repeat(" ",  17) . "word", getline(1))
+  norm! V3>
+  call assert_equal(repeat(" ",  32) . "word", getline(1))
+
+  norm! V<
+  call assert_equal(repeat(" ",  27) . "word", getline(1))
+  norm! V2<
+  call assert_equal(repeat(" ",  17) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "  word")
+
+  norm! V>
+  call assert_equal(repeat(" ",  9) . "word", getline(1))
+  norm! V2>
+  call assert_equal(repeat(" ",  23) . "word", getline(1))
+  norm! V3>
+  call assert_equal(repeat(" ",  44) . "word", getline(1))
+
+  norm! V<
+  call assert_equal(repeat(" ",  37) . "word", getline(1))
+  norm! V2<
+  call assert_equal(repeat(" ",  23) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the V> and V< visual-mode commands, with 'vartabstop'.
+"
+" See ":help v_<" and ":help v_>".  See also the last paragraph of "3. Simple
+" changes", ":help simple-change", immediately above "4. Complex changes",
+" ":help complex-change".
+"
+func Test_shift_vis_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "  word")
+
+  norm! V>
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! V2>
+  call assert_equal(repeat(" ",  49) . "word", getline(1))
+  norm! V3>
+  call assert_equal(repeat(" ",  82) . "word", getline(1))
+
+  norm! V<
+  call assert_equal(repeat(" ",  71) . "word", getline(1))
+  norm! V2<
+  call assert_equal(repeat(" ",  49) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test the V> and V< visual-mode commands with 'shiftround'.
+"
+func Test_shift_vis_round()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  exe "norm! I  "
+  norm! V>
+  call assert_equal(repeat(" ",  5) . "word", getline(1))
+  exe "norm! I  "
+  norm! V2>
+  call assert_equal(repeat(" ",  15) . "word", getline(1))
+  exe "norm! I  "
+  norm! V3>
+  call assert_equal(repeat(" ",  30) . "word", getline(1))
+
+  exe "norm! I  "
+  norm! V2<
+  call assert_equal(repeat(" ",  25) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  10) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  5) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "word")
+
+  exe "norm! I  "
+  norm! V>
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  exe "norm! I  "
+  norm! V2>
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  exe "norm! I  "
+  norm! V3>
+  call assert_equal(repeat(" ",  42) . "word", getline(1))
+
+  exe "norm! I  "
+  norm! V<
+  call assert_equal(repeat(" ",  42) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  35) . "word", getline(1))
+  norm! V2<
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  call setline(1, "  word")
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+
+  set expandtab& shiftround& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the V> and V< visual-mode commands with 'shiftround' and 'vartabstop'.
+"
+func Test_shift_vis_round_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "word")
+
+  exe "norm! I  "
+  norm! V>
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  norm! V3>
+  call assert_equal(repeat(" ",  58) . "word", getline(1))
+
+  exe "norm! I  "
+  norm! V2<
+  call assert_equal(repeat(" ",  47) . "word", getline(1))
+  exe "norm! I  "
+  norm! V3<
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  norm! V3<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  exe "norm! I  "
+  norm! V<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftround& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test the :> and :< ex-mode commands.
+"
+func Test_shift_ex()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "  word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  >
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  >>
+  call assert_equal(repeat(" ",  17) . "word", getline(1))
+  >>>
+  call assert_equal(repeat(" ",  32) . "word", getline(1))
+
+  <<<<
+  call assert_equal(repeat(" ",  12) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "  word")
+
+  >
+  call assert_equal(repeat(" ",  9) . "word", getline(1))
+  >>
+  call assert_equal(repeat(" ",  23) . "word", getline(1))
+  >>>
+  call assert_equal(repeat(" ",  44) . "word", getline(1))
+
+  <<<<
+  call assert_equal(repeat(" ",  16) . "word", getline(1))
+  <<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the :> and :< ex-mode commands, with vartabstop.
+"
+func Test_shift_ex_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "  word")
+
+  >
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  >>
+  call assert_equal(repeat(" ",  49) . "word", getline(1))
+  >>>
+  call assert_equal(repeat(" ",  82) . "word", getline(1))
+
+  <<<<
+  call assert_equal(repeat(" ",  38) . "word", getline(1))
+  <<
+  call assert_equal(repeat(" ",  2) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test the :> and :< ex-mode commands with 'shiftround'.
+"
+func Test_shift_ex_round()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=5
+  set tabstop=7
+
+  call setline(1, "word")
+
+  " Shift by 'shiftwidth' right and left.
+
+  exe "norm! I  "
+  >
+  call assert_equal(repeat(" ",  5) . "word", getline(1))
+  exe "norm! I  "
+  >>
+  call assert_equal(repeat(" ",  15) . "word", getline(1))
+  exe "norm! I  "
+  >>>
+  call assert_equal(repeat(" ",  30) . "word", getline(1))
+
+  exe "norm! I  "
+  <<<<
+  call assert_equal(repeat(" ",  15) . "word", getline(1))
+  exe "norm! I  "
+  <<
+  call assert_equal(repeat(" ",  10) . "word", getline(1))
+  <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  >>
+  <<<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "word")
+
+  exe "norm! I  "
+  >
+  call assert_equal(repeat(" ",  7) . "word", getline(1))
+  exe "norm! I  "
+  >>
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  exe "norm! I  "
+  >>>
+  call assert_equal(repeat(" ",  42) . "word", getline(1))
+
+  exe "norm! I  "
+  <<<<
+  call assert_equal(repeat(" ",  21) . "word", getline(1))
+  exe "norm! I  "
+  <<
+  call assert_equal(repeat(" ",  14) . "word", getline(1))
+  exe "norm! I  "
+  <<<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  >>
+  <<<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftround& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test the :> and :< ex-mode commands with 'shiftround' and 'vartabstop'.
+"
+func Test_shift_ex_round_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftround
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "word")
+
+  exe "norm! I  "
+  >
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  >>
+  call assert_equal(repeat(" ",  47) . "word", getline(1))
+  >>>
+  call assert_equal(repeat(" ",  80) . "word", getline(1))
+
+  <<<<
+  call assert_equal(repeat(" ",  36) . "word", getline(1))
+  exe "norm! I  "
+  <<
+  call assert_equal(repeat(" ",  19) . "word", getline(1))
+  exe "norm! I  "
+  <<
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+  <
+  call assert_equal(repeat(" ",  0) . "word", getline(1))
+
+  set expandtab& shiftround& shiftwidth& vartabstop&
+  bw!
+endfunc
+
+" Test shifting lines with <C-T> and <C-D>.
+"
+func Test_shift_ins()
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=5
+  set tabstop=7
+
+  " Shift by 'shiftwidth' right and left.
+
+  call setline(1, repeat(" ", 7) . "word")
+  exe "norm! 9|i\<C-T>"
+  call assert_equal(repeat(" ", 10) . "word", getline(1))
+  exe "norm! A\<C-T>"
+  call assert_equal(repeat(" ", 15) . "word", getline(1))
+  exe "norm! I  \<C-T>"
+  call assert_equal(repeat(" ", 20) . "word", getline(1))
+
+  exe "norm! I  \<C-D>"
+  call assert_equal(repeat(" ", 20) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! 24|i\<C-D>"
+  call assert_equal(repeat(" ", 20) . "word", getline(1))
+  exe "norm! A\<C-D>"
+  call assert_equal(repeat(" ", 15) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! A\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 10) . "word", getline(1))
+  exe "norm! I\<C-D>\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+  exe "norm! I\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+
+  " Shift by 'tabstop' right and left.
+
+  set shiftwidth=0
+  call setline(1, "word")
+
+  call setline(1, repeat(" ", 9) . "word")
+  exe "norm! 11|i\<C-T>"
+  call assert_equal(repeat(" ", 14) . "word", getline(1))
+  exe "norm! A\<C-T>"
+  call assert_equal(repeat(" ", 21) . "word", getline(1))
+  exe "norm! I  \<C-T>"
+  call assert_equal(repeat(" ", 28) . "word", getline(1))
+
+  exe "norm! I  \<C-D>"
+  call assert_equal(repeat(" ", 28) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! 32|i\<C-D>"
+  call assert_equal(repeat(" ", 28) . "word", getline(1))
+  exe "norm! A\<C-D>"
+  call assert_equal(repeat(" ", 21) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! A\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 14) . "word", getline(1))
+  exe "norm! I\<C-D>\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+  exe "norm! I\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+
+  set expandtab& shiftwidth& tabstop&
+  bw!
+endfunc
+
+" Test shifting lines with <C-T> and <C-D>, with 'vartabstop'.
+"
+func Test_shift_ins_vartabs()
+  CheckFeature vartabs
+  set expandtab                 " Don't want to worry about tabs vs. spaces in
+                                " results.
+
+  set shiftwidth=0
+  set vartabstop=19,17,11
+
+  " Shift by 'vartabstop' right and left.
+
+  call setline(1, "word")
+
+  call setline(1, repeat(" ", 9) . "word")
+  exe "norm! 11|i\<C-T>"
+  call assert_equal(repeat(" ", 19) . "word", getline(1))
+  exe "norm! A\<C-T>"
+  call assert_equal(repeat(" ", 36) . "word", getline(1))
+  exe "norm! I  \<C-T>"
+  call assert_equal(repeat(" ", 47) . "word", getline(1))
+
+  exe "norm! I  \<C-D>"
+  call assert_equal(repeat(" ", 47) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! 51|i\<C-D>"
+  call assert_equal(repeat(" ", 47) . "word", getline(1))
+  exe "norm! A\<C-D>"
+  call assert_equal(repeat(" ", 36) . "word", getline(1))
+  exe "norm! I  "
+  exe "norm! A\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 19) . "word", getline(1))
+  exe "norm! I\<C-D>\<C-D>\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+  exe "norm! I\<C-D>"
+  call assert_equal(repeat(" ", 0) . "word", getline(1))
+
+  set expandtab& shiftwidth& vartabstop&
+  bw!
 endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab