done implementing tests for yank. Also simplify 'NormalDelete.deleteLineDown' and 'NormalYank.yankLineDown' functions by removing an if-branch which can never trigger. (The code path can only be executed in the event that 'endLineIdx' is on a newline, and there is an if-expression in that branch checking whether 'endLineIdx' is on a newline, which is redundant.)

fcore/normal-mode/make-normal-delete.sml

@@ -549,29 +549,26 @@ struct
         let
           val buffer = LineGap.goToIdx (endLineIdx, buffer)
 
-          (* right now, endLineIdx may be on a newline.
-           * If it is, we want to delete that newline too,
-           * and in that case, we increment by 1 to do so. 
+          (* endLineIdx is on a newline because it was retrieved 
+           * by calling the `LineGap.lineNumberToIdx` function, 
+           * which always returns the idx of a line break.
+           * Since that is the case, we want to delete that newline too,
+           * and we increment by 1 to do so. 
            * However, we don't want to delete the last newline in the file
            * so we don't increment in that case. 
            * Edge case: if the startIdx also begins after a newline
            * then it is okay for us to delete the newline at the end of the file
            * because there will already be a newline at the end of the file
            * after the deletion. *)
-          val endsOnNewline = Cursor.isCursorAtStartOfLine (buffer, endLineIdx)
-
           val buffer = LineGap.goToIdx (startIdx, buffer)
           val startsAfterNewline =
             startIdx > 0 andalso Cursor.isPrevChrStartOfLine (buffer, startIdx)
 
           val endLineIdx =
-            if endsOnNewline then
-              if endLineIdx = #textLength buffer - 1 then
-                if startsAfterNewline then endLineIdx + 1 else endLineIdx
-              else
-                endLineIdx + 1
+            if endLineIdx = #textLength buffer - 1 then
+              if startsAfterNewline then endLineIdx + 1 else endLineIdx
             else
-              endLineIdx
+              endLineIdx + 1
 
           val length = endLineIdx - startIdx
 

fcore/normal-mode/normal-yank.sml

@@ -130,13 +130,7 @@ struct
         NormalFinish.clearMode app
       else
         let
-          val buffer = LineGap.goToIdx (endLineIdx, buffer)
-          val endLineIdx =
-            if Cursor.isCursorAtStartOfLine (buffer, endLineIdx) then
-              endLineIdx + 1
-            else
-              endLineIdx
-
+          val endLineIdx = endLineIdx + 1
           val length = endLineIdx - startIdx
 
           (* perform the actual yank *)

test/normal-yank-tests.sml

@@ -428,7 +428,105 @@ struct
            in
              TestUtils.expectYank (app, expectedString)
            end)
-        ]
+    , test
+        "yanks first two lines when there are three lines \
+        \and cursor is on first line"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalIdx = 0
+             val originalString = "hello\nworld\nbye world\n"
+
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, originalIdx)
+
+             (* act *)
+             val app = TestUtils.updateMany (app, "yj")
+
+             (* assert *)
+             val expectedString = "hello\nworld\n"
+           in
+             TestUtils.expectYank (app, expectedString)
+           end)
+    , test
+        "yanks last two lines when there are three lines \
+        \and cursor is on second line"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalIdx = 6
+             val originalString = "hello\nworld\nbye world\n"
+
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, originalIdx)
+
+             (* act *)
+             val app = TestUtils.updateMany (app, "yj")
+
+             (* assert *)
+             val expectedString = "world\nbye world\n"
+           in
+             TestUtils.expectYank (app, expectedString)
+           end)
+    , test
+        "yanks entire file when cursor is on first line \
+        \and a count is given which is larger \
+        \than the total number of lines in the file"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalString = "hello\nworld\n"
+             val originalIdx = 0
+
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, originalIdx)
+
+             (* act *)
+             val app = TestUtils.updateMany (app, "33yj")
+
+             (* assert *)
+             val expectedString = originalString
+           in
+             TestUtils.expectYank (app, expectedString)
+           end)
+    , test
+        "yanks entire file when a count greater than the total number of lines \
+        \is given, while the file does not end with a newline"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalString = "hello\nworld"
+             val originalIdx = 0
+
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, originalIdx)
+
+             (* act *)
+             val app = TestUtils.updateMany (app, "33yj")
+
+             (* assert *)
+             val expectedString = originalString
+           in
+             TestUtils.expectYank (app, expectedString)
+           end)
+    , test "yanks two lines when cursor is on a newline" (fn _ =>
+        let
+          (* arrange *)
+          val originalString = "\nhello\nworld\ntrello\nbrillo\n"
+          val originalIdx = 0
+
+          val app = TestUtils.init originalString
+          val app = AppWith.idx (app, originalIdx)
+
+          (* act *)
+          val app = TestUtils.updateMany (app, "yj")
+
+          (* assert *)
+          val expectedString = "\nhello\n"
+        in
+          TestUtils.expectYank (app, expectedString)
+        end)
+    ]
 
   val tests = [yhYank, ylYank, ykYank, yjYank]
 end

todo.md

@@ -1,4 +1,5 @@
 # To-do list
-- Add tests for 'yj' motion
+- Add tests for other yank motoins
+  - Tests should be based on existing tests for delete-motions, and in the same order.
 - Bind gamepad functions from GLFW and/or RGFW
 - Add tests for NormalYankDelete functions, to make sure that they are yanking the expected string.