cursor fix, test adjustments (akvelon#185)

Co-authored-by: Yestay Tastanov <yestay@Yestays-MacBook-Pro.local>

Author: yescorp

lib/src/code_field/code_controller.dart

@@ -362,11 +362,21 @@ class CodeController extends TextEditingController {
         return;
       }
 
+      final selectionSnapshot =
+          code.hiddenRanges.recoverSelection(newValue.selection);
       _updateCodeIfChanged(editResult.fullTextAfter);
 
       if (newValue.text != _code.visibleText) {
-        // Manually typed in a text that has become a hidden range.
-        newValue = newValue.replacedText(_code.visibleText);
+        if (newValue.text.length > _code.visibleText.length) {
+          // Manually typed in a text that has become a hidden range.
+          newValue = newValue.replacedText(_code.visibleText);
+        } else {
+          // Some folded block is unfolded.
+          newValue = TextEditingValue(
+            text: _code.visibleText,
+            selection: _code.hiddenRanges.cutSelection(selectionSnapshot),
+          );
+        }
       }
 
       // Uncomment this to see the hidden text in the console

test/src/code_field/code_controller_folding_editing_test.dart

@@ -215,9 +215,11 @@ int n;
 
             await wt.cursorEnd();
             controller.value = controller.value.replacedSelection(inserted);
-            // TODO(yescorp): Fix selection, then fix tests
-            //  https://github.com/akvelon/flutter-code-editor/issues/182
             expect(controller.value.text, example + inserted);
+            expect(
+              controller.value.selection,
+              TextSelection.collapsed(offset: controller.value.text.length),
+            );
             expect(controller.code.foldedBlocks.length, 0);
           });
 
@@ -251,9 +253,11 @@ int n;
 
             await wt.cursorEnd();
             controller.value = controller.value.replacedSelection(inserted);
-            // TODO(yescorp): Fix selection, then fix tests
-            //  https://github.com/akvelon/flutter-code-editor/issues/182
             expect(controller.value.text, example + inserted);
+            expect(
+              controller.value.selection,
+              TextSelection.collapsed(offset: controller.value.text.length),
+            );
             expect(controller.code.foldedBlocks.length, 0);
           });
 
@@ -296,8 +300,12 @@ int n;
             controller.value = controller.value.replacedSelection('  bbbb');
 
             const expectedText = 'a:\n  aaaa\n  bbbb';
-
+            //                                      \ selection
             expect(controller.value.text, expectedText);
+            expect(
+              controller.value.selection,
+              TextSelection.collapsed(offset: controller.value.text.length),
+            );
             expect(controller.code.foldedBlocks.length, 0);
           });