test: added some more tests to confirm the undo tree is "good"

Yay! These are from Sonnet 4.0, hope theyre good.

internal/editor/integration_undo_test.go

@@ -6,6 +6,19 @@ import (
 	"git.gophernest.net/azpect/TextEditor/internal/core"
 )
 
+// equalStringSlices compares two string slices for equality
+func equalStringSlices(a, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
+
 // ============================================================================
 // BASIC UNDO/REDO TESTS
 // ============================================================================
@@ -747,3 +760,233 @@ func TestUndoComplexScenarios(t *testing.T) {
 		}
 	})
 }
+
+// =================================================================
+// PASTE OPERATIONS TESTS
+// =================================================================
+
+func TestUndoPasteOperations(t *testing.T) {
+	t.Run("basic p (paste after) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"line1", "line2"})
+
+		// Yank first line and paste after second line
+		sendKeys(tm, "y", "y") // yank current line (line1)
+		sendKeys(tm, "j")      // move to line2
+		sendKeys(tm, "p")      // paste after line2
+		sendKeys(tm, "u")      // undo paste
+
+		m := getFinalModel(t, tm)
+		expected := []string{"line1", "line2"}
+		if len(m.ActiveBuffer().Lines) != len(expected) {
+			t.Errorf("len(Lines) = %d, want %d", len(m.ActiveBuffer().Lines), len(expected))
+		}
+		for i, exp := range expected {
+			if m.ActiveBuffer().Lines[i] != exp {
+				t.Errorf("Lines[%d] = %q, want %q", i, m.ActiveBuffer().Lines[i], exp)
+			}
+		}
+		// Cursor should be back at line2
+		if m.ActiveWindow().Cursor.Line != 1 {
+			t.Errorf("Cursor.Line = %d, want 1", m.ActiveWindow().Cursor.Line)
+		}
+	})
+
+	t.Run("basic P (paste before) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"line1", "line2"})
+
+		// Yank first line and paste before second line
+		sendKeys(tm, "y", "y") // yank current line (line1)
+		sendKeys(tm, "j")      // move to line2
+		sendKeys(tm, "P")      // paste before line2
+		sendKeys(tm, "u")      // undo paste
+
+		m := getFinalModel(t, tm)
+		expected := []string{"line1", "line2"}
+		if len(m.ActiveBuffer().Lines) != len(expected) {
+			t.Errorf("len(Lines) = %d, want %d", len(m.ActiveBuffer().Lines), len(expected))
+		}
+		for i, exp := range expected {
+			if m.ActiveBuffer().Lines[i] != exp {
+				t.Errorf("Lines[%d] = %q, want %q", i, m.ActiveBuffer().Lines[i], exp)
+			}
+		}
+		// Cursor should be back at line2
+		if m.ActiveWindow().Cursor.Line != 1 {
+			t.Errorf("Cursor.Line = %d, want 1", m.ActiveWindow().Cursor.Line)
+		}
+	})
+
+	t.Run("charwise paste undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"hello world"})
+
+		// Yank "hello" and paste after "world"
+		sendKeys(tm, "y", "w") // yank word "hello"
+		sendKeys(tm, "$")      // move to end
+		sendKeys(tm, "p")      // paste after cursor
+		sendKeys(tm, "u")      // undo paste
+
+		m := getFinalModel(t, tm)
+		expected := []string{"hello world"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+
+	t.Run("visual mode paste undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"hello world", "foo bar"})
+
+		// Yank "hello" then select "world" and paste over it
+		sendKeys(tm, "y", "w") // yank "hello"
+		sendKeys(tm, "w")      // move to "world"
+		sendKeys(tm, "v", "e") // select "world"
+		sendKeys(tm, "p")      // paste over selection
+		sendKeys(tm, "u")      // undo paste
+
+		m := getFinalModel(t, tm)
+		expected := []string{"hello world", "foo bar"}
+		if len(m.ActiveBuffer().Lines) != len(expected) {
+			t.Errorf("len(Lines) = %d, want %d", len(m.ActiveBuffer().Lines), len(expected))
+		}
+		for i, exp := range expected {
+			if m.ActiveBuffer().Lines[i] != exp {
+				t.Errorf("Lines[%d] = %q, want %q", i, m.ActiveBuffer().Lines[i], exp)
+			}
+		}
+	})
+
+	t.Run("multiple paste operations undo separately", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"base"})
+
+		sendKeys(tm, "y", "y") // yank "base"
+		sendKeys(tm, "p")      // paste: "base\nbase"
+		sendKeys(tm, "p")      // paste: "base\nbase\nbase"
+		sendKeys(tm, "u")      // undo last paste: "base\nbase"
+		sendKeys(tm, "u")      // undo first paste: "base"
+
+		m := getFinalModel(t, tm)
+		expected := []string{"base"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+
+	t.Run("paste with count undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"test"})
+
+		sendKeys(tm, "y", "y")  // yank "test"
+		sendKeyString(tm, "3p") // paste 3 times
+		sendKeys(tm, "u")       // undo (should undo all 3 pastes as one block)
+
+		m := getFinalModel(t, tm)
+		expected := []string{"test"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+}
+
+// =================================================================
+// COMPLEX COUNT OPERATIONS TESTS
+// =================================================================
+
+func TestUndoComplexCountOperations(t *testing.T) {
+	t.Run("5dd undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"1", "2", "3", "4", "5", "6", "7"})
+
+		sendKeys(tm, "j", "j")   // move to line 3
+		sendKeyString(tm, "5dd") // delete 5 lines (3,4,5,6,7)
+		sendKeys(tm, "u")        // undo
+
+		m := getFinalModel(t, tm)
+		expected := []string{"1", "2", "3", "4", "5", "6", "7"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+		// Cursor should be back at line 3 (index 2)
+		if m.ActiveWindow().Cursor.Line != 2 {
+			t.Errorf("Cursor.Line = %d, want 2", m.ActiveWindow().Cursor.Line)
+		}
+	})
+
+	t.Run("3cw (change 3 words) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"one two three four five"})
+
+		sendKeys(tm, "3", "c", "w") // change 3 words
+		sendKeys(tm, "CHANGED")     // type replacement
+		sendKeys(tm, "esc")         // exit insert mode
+		sendKeys(tm, "u")           // undo
+
+		m := getFinalModel(t, tm)
+		expected := []string{"one two three four five"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+
+	t.Run("10x (delete 10 chars) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"abcdefghijklmnopqrstuvwxyz"})
+
+		sendKeys(tm, "5", "|")   // move to column 5 (f)
+		sendKeyString(tm, "10x") // delete 10 chars (fghijklmno)
+		sendKeys(tm, "u")        // undo
+
+		m := getFinalModel(t, tm)
+		expected := []string{"abcdefghijklmnopqrstuvwxyz"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+		// Cursor should be back at column 4 (index of 'e', 0-based)
+		if m.ActiveWindow().Cursor.Col != 4 {
+			t.Errorf("Cursor.Col = %d, want 4", m.ActiveWindow().Cursor.Col)
+		}
+	})
+
+	t.Run("2cc (change 2 lines) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"line1", "line2", "line3", "line4"})
+
+		sendKeys(tm, "j")           // move to line2
+		sendKeys(tm, "2", "c", "c") // change 2 lines (line2, line3)
+		sendKeys(tm, "NEW", "LINE") // type replacement
+		sendKeys(tm, "esc")         // exit insert mode
+		sendKeys(tm, "u")           // undo
+
+		m := getFinalModel(t, tm)
+		expected := []string{"line1", "line2", "line3", "line4"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+
+	t.Run("4diw (delete 4 words) undo", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"word1 word2 word3 word4 word5"})
+
+		sendKeys(tm, "w")         // move to word2
+		sendKeyString(tm, "4diw") // delete 4 words (word2, word3, word4, word5)
+		sendKeys(tm, "u")         // undo
+
+		m := getFinalModel(t, tm)
+		expected := []string{"word1 word2 word3 word4 word5"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+	})
+
+	t.Run("complex count with paste: 3p after 2yy", func(t *testing.T) {
+		tm := newTestModelWithLines(t, []string{"A", "B", "C", "D"})
+
+		sendKeyString(tm, "2yy") // yank 2 lines (A, B)
+		sendKeys(tm, "j", "j")   // move to line C
+		sendKeyString(tm, "3p")  // paste 3 times
+		sendKeys(tm, "u")        // undo paste
+
+		m := getFinalModel(t, tm)
+		expected := []string{"A", "B", "C", "D"}
+		if !equalStringSlices(m.ActiveBuffer().Lines, expected) {
+			t.Errorf("Lines = %v, want %v", m.ActiveBuffer().Lines, expected)
+		}
+		// Cursor should be back at line C (index 2)
+		if m.ActiveWindow().Cursor.Line != 2 {
+			t.Errorf("Cursor.Line = %d, want 2", m.ActiveWindow().Cursor.Line)
+		}
+	})
+}