1 files changed, 112 insertions, 0 deletions
diff --git a/test/functional/lua/xdiff_spec.lua b/test/functional/lua/xdiff_spec.lua
new file mode 100644
index 0000000000..4f28f84c01
--- /dev/null
+++ b/test/functional/lua/xdiff_spec.lua
@@ -0,0 +1,112 @@
+local helpers = require('test.functional.helpers')(after_each)
+local clear = helpers.clear
+local exec_lua = helpers.exec_lua
+local eq = helpers.eq
+local pcall_err = helpers.pcall_err
+
+describe('xdiff bindings', function()
+  before_each(function()
+    clear()
+  end)
+
+  describe('can diff text', function()
+    before_each(function()
+      exec_lua[[
+        a1 = 'Hello\n'
+        b1 = 'Helli\n'
+
+        a2 = 'Hello\nbye\nfoo\n'
+        b2 = 'Helli\nbye\nbar\nbaz\n'
+      ]]
+    end)
+
+    it('with no callback', function()
+
+      eq(
+        table.concat({
+          '@@ -1 +1 @@',
+          '-Hello',
+          '+Helli',
+          ''
+        }, '\n'),
+        exec_lua("return vim.diff(a1, b1)")
+      )
+
+      eq(
+        table.concat({
+          '@@ -1 +1 @@',
+          '-Hello',
+          '+Helli',
+          '@@ -3 +3,2 @@',
+          '-foo',
+          '+bar',
+          '+baz',
+          ''
+        }, '\n'),
+        exec_lua("return vim.diff(a2, b2)")
+      )
+
+    end)
+
+    it('with callback', function()
+      exec_lua([[on_hunk = function(sa, ca, sb, cb)
+          exp[#exp+1] = {sa, ca, sb, cb}
+        end]])
+
+      eq({{1, 1, 1, 1}}, exec_lua[[
+          exp = {}
+          assert(vim.diff(a1, b1, {on_hunk = on_hunk}) == nil)
+          return exp
+        ]])
+
+      eq({{1, 1, 1, 1}, {3, 1, 3, 2}}, exec_lua[[
+          exp = {}
+          assert(vim.diff(a2, b2, {on_hunk = on_hunk}) == nil)
+          return exp
+        ]])
+
+      -- gives higher precedence to on_hunk over result_type
+      eq({{1, 1, 1, 1}, {3, 1, 3, 2}}, exec_lua[[
+          exp = {}
+          assert(vim.diff(a2, b2, {on_hunk = on_hunk, result_type='indices'}) == nil)
+          return exp
+        ]])
+    end)
+
+    it('with error callback', function()
+      exec_lua([[on_hunk = function(sa, ca, sb, cb)
+          error('ERROR1')
+        end]])
+
+      eq([[Error executing lua: [string "<nvim>"]:0: error running function on_hunk: [string "<nvim>"]:0: ERROR1]],
+        pcall_err(exec_lua, [[vim.diff(a1, b1, {on_hunk = on_hunk})]]))
+    end)
+
+    it('with hunk_lines', function()
+      eq({{1, 1, 1, 1}},
+        exec_lua([[return vim.diff(a1, b1, {result_type = 'indices'})]]))
+
+      eq({{1, 1, 1, 1}, {3, 1, 3, 2}},
+        exec_lua([[return vim.diff(a2, b2, {result_type = 'indices'})]]))
+    end)
+
+  end)
+
+  it('can handle bad args', function()
+    eq([[Error executing lua: [string "<nvim>"]:0: Expected at least 2 arguments]],
+      pcall_err(exec_lua, [[vim.diff('a')]]))
+
+    eq([[Error executing lua: [string "<nvim>"]:0: bad argument #1 to 'diff' (expected string)]],
+      pcall_err(exec_lua, [[vim.diff(1, 2)]]))
+
+    eq([[Error executing lua: [string "<nvim>"]:0: bad argument #3 to 'diff' (expected table)]],
+      pcall_err(exec_lua, [[vim.diff('a', 'b', true)]]))
+
+    eq([[Error executing lua: [string "<nvim>"]:0: unexpected key: bad_key]],
+      pcall_err(exec_lua, [[vim.diff('a', 'b', { bad_key = true })]]))
+
+    eq([[Error executing lua: [string "<nvim>"]:0: on_hunk is not a function]],
+      pcall_err(exec_lua, [[vim.diff('a', 'b', { on_hunk = true })]]))
+
+  end)
+end)