add some more tests for 'df<char' motion, and fix implementation to pass those tests (if our cursor is at the same position after calling 'fMove', then exit the loop to find the next occurrence of <char>)

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

@@ -677,9 +677,7 @@ struct
       deleteAndFinish (app, low, length, buffer, time)
     end
 
-  fun helpDeleteToChr
-    (app: app_type, buffer, cursorIdx, otherIdx, count, fMove, fInc, chr, time) =
-    if count = 0 then
+  fun finishDeleteToChr (app, buffer, cursorIdx, otherIdx, time) =
     let
       val low = Int.min (cursorIdx, otherIdx)
       val high = Int.max (cursorIdx, otherIdx)
@@ -687,19 +685,25 @@ struct
     in
       deleteAndFinish (app, low, length, buffer, time)
     end
+
+  fun helpDeleteToChr
+    (app: app_type, buffer, cursorIdx, otherIdx, count, fMove, fInc, chr, time) =
+    if count = 0 then
+      finishDeleteToChr (app, buffer, cursorIdx, otherIdx, time)
     else
       let
         val buffer = LineGap.goToIdx (otherIdx, buffer)
         val newOtherIdx = fMove (buffer, otherIdx, chr)
-        val newCount = if newOtherIdx = otherIdx then 0 else count - 1
-        val newOtherIdx = fInc (newOtherIdx, 1)
       in
+        if otherIdx = newOtherIdx then
+          finishDeleteToChr (app, buffer, cursorIdx, otherIdx, time)
+        else
           helpDeleteToChr
             ( app
             , buffer
             , cursorIdx
-          , newOtherIdx
-          , newCount
+            , fInc (newOtherIdx, 1)
+            , count - 1
             , fMove
             , fInc
             , chr

test/normal-delete.sml

@@ -3531,6 +3531,51 @@ struct
                (actualString = expectedString
                 andalso cursorIdx = expectedCursorIdx)
            end)
+    , test
+        "deletes from cursor's position to second occurrence of <char> \
+        \if motion has a count of 2"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalString = "hello\nworld\n"
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, 0)
+
+             (* act *)
+             val {buffer, cursorIdx, ...} = TestUtils.updateMany (app, "2dfo")
+
+             (* assert *)
+             val actualString = LineGap.toString buffer
+             val expectedString = "rld\n"
+             val expectedCursorIdx = 0
+           in
+             Expect.isTrue
+               (actualString = expectedString
+                andalso cursorIdx = expectedCursorIdx)
+           end)
+    , test
+        "deletes from cursor's position to last occurrence of <char> \
+        \if motion has a count greater than \
+        \the number of occurences of <char>, after the cursor"
+        (fn _ =>
+           let
+             (* arrange *)
+             val originalString = "hello\nworld\n"
+             val app = TestUtils.init originalString
+             val app = AppWith.idx (app, 0)
+
+             (* act *)
+             val {buffer, cursorIdx, ...} = TestUtils.updateMany (app, "99dfl")
+
+             (* assert *)
+             val actualString = LineGap.toString buffer
+             val expectedString = "d\n"
+             val expectedCursorIdx = 0
+           in
+             Expect.isTrue
+               (actualString = expectedString
+                andalso cursorIdx = expectedCursorIdx)
+           end)
     ]
 
   val tests =

todo.md

@@ -1,7 +1,6 @@
 # To-do list
 
 - Add tests for:
-  - `df<char>`
   - `dF<char>`
   - `dt<char>`
   - `dT<char>`