Add missing unit tests for Surface.SetMany and Surface.LinesIterator

pitest/pitest.go

@@ -37,7 +37,7 @@ func AssertSurfaceEqual[T comparable](t *testing.T, expected, actual pi.Surface[
 				if !hasDifferentData {
 					t.Errorf("\nexpected:\n%s\nactual:\n%s", expected, actual)
 				}
-				t.Errorf("expected pixel at (%d,%d): %v, actual: %v", x, y, e, a)
+				t.Errorf("expected at (%d,%d): %v, actual: %v", x, y, e, a)
 				hasDifferentData = true
 				equal = false
 			}

surface.go

@@ -243,7 +243,7 @@ func (m Surface[T]) EntireArea() IntArea {
 }
 
 func (m Surface[T]) Clear(v T) {
-	// color only first line
+	// color only the first line
 	var firstLine = m.data[:m.width]
 	for i := 0; i < m.width; i++ {
 		firstLine[i] = v

surface_test.go

@@ -207,14 +207,52 @@ func TestSurface_SetSurface(t *testing.T) {
 }
 
 func TestSurface_LinesIterator(t *testing.T) {
-	// temporary test
-	surface := pi.NewSurface[int](2, 2)
-	for range surface.LinesIterator(pi.IntArea{W: 2, H: 2}) {
-	}
+	surface := pi.NewSurface[rune](4, 3)
+	surface.SetAll(
+		'a', 'b', 'c', 'd',
+		'e', 'f', 'g', 'h',
+		'i', 'j', 'k', 'l',
+	)
+
+	t.Run("iterate over area", func(t *testing.T) {
+		area := pi.IntArea{X: 1, Y: 1, W: 2, H: 2}
+		expectedPos := []pi.Position{
+			{1, 1},
+			{1, 2},
+		}
+		expectedLines := [][]rune{
+			{'f', 'g'},
+			{'j', 'k'},
+		}
+
+		var i int
+		for pos, line := range surface.LinesIterator(area) {
+			require.Less(t, i, len(expectedPos))
+			assert.Equal(t, expectedPos[i], pos)
+			assert.Equal(t, expectedLines[i], line)
+			i++
+		}
+		assert.Equal(t, len(expectedPos), i)
+	})
+
+	t.Run("modifies underlying data", func(t *testing.T) {
+		area := pi.IntArea{X: 1, Y: 1, W: 2, H: 1}
+		for _, line := range surface.LinesIterator(area) {
+			line[0] = 'z'
+		}
+		assert.Equal(t, 'z', surface.Get(1, 1))
+	})
+
+	t.Run("panic on area outside surface", func(t *testing.T) {
+		area := pi.IntArea{X: -1, Y: 0, W: 2, H: 1}
+		require.Panics(t, func() {
+			for range surface.LinesIterator(area) {
+			}
+		})
+	})
 }
 
 func BenchmarkSurface_LinesIterator(b *testing.B) {
-	// temporary test
 	surface := pi.NewSurface[int](2, 2)
 	area := pi.IntArea{W: 2, H: 2}
 	b.ResetTimer()
@@ -227,18 +265,71 @@ func BenchmarkSurface_LinesIterator(b *testing.B) {
 }
 
 func TestSurface_SetMany(t *testing.T) {
-	// temporary test
-	canvas := pi.NewCanvas(4, 4)
-	canvas.SetMany(1, 1,
-		2, 3, 4, 5)
-	canvas.SetMany(-1, 0,
-		2, 3, 4, 5)
-	canvas.SetMany(0, -1,
-		2, 3, 4, 5)
-	canvas.SetMany(3, 3,
-		2, 3, 4, 5)
-	canvas.SetMany(4, 4,
-		2, 3, 4, 5)
+	t.Run("inside surface", func(t *testing.T) {
+		surface := pi.NewSurface[rune](3, 2)
+		// when
+		surface.SetMany(1, 0, 'a', 'b', 'c', 'd')
+		// then
+		expected := pi.NewSurface[rune](3, 2)
+		expected.Set(1, 0, 'a')
+		expected.Set(2, 0, 'b')
+		expected.Set(0, 1, 'c')
+		expected.Set(1, 1, 'd')
+
+		pitest.AssertSurfaceEqual(t, expected, surface)
+	})
+
+	t.Run("partially outside left", func(t *testing.T) {
+		surface := pi.NewSurface[rune](3, 2)
+		// when
+		surface.SetMany(-1, 0, 'a', 'b', 'c')
+		// then
+		expected := pi.NewSurface[rune](3, 2)
+		expected.Set(0, 0, 'b')
+		expected.Set(1, 0, 'c')
+
+		pitest.AssertSurfaceEqual(t, expected, surface)
+	})
+
+	t.Run("partially outside top", func(t *testing.T) {
+		surface := pi.NewSurface[rune](2, 2)
+		// when
+		surface.SetMany(0, -1, 'a', 'b', 'c')
+		// then
+		expected := pi.NewSurface[rune](2, 2)
+		expected.Set(0, 0, 'c')
+
+		pitest.AssertSurfaceEqual(t, expected, surface)
+	})
+
+	t.Run("start far left with too few values", func(t *testing.T) {
+		surface := pi.NewSurface[rune](2, 2)
+		original := surface.Clone()
+		// when
+		surface.SetMany(-3, 0, 'a')
+		// then
+		pitest.AssertSurfaceEqual(t, original, surface)
+	})
+
+	t.Run("outside bottom-right", func(t *testing.T) {
+		surface := pi.NewSurface[rune](2, 2)
+		original := surface.Clone()
+		// when
+		surface.SetMany(2, 2, 'a', 'b')
+		// then
+		pitest.AssertSurfaceEqual(t, original, surface)
+	})
+
+	t.Run("truncate at surface end", func(t *testing.T) {
+		surface := pi.NewSurface[rune](2, 2)
+		// when
+		surface.SetMany(1, 1, 'a', 'b')
+		// then
+		expected := pi.NewSurface[rune](2, 2)
+		expected.Set(1, 1, 'a')
+
+		pitest.AssertSurfaceEqual(t, expected, surface)
+	})
 }
 
 func TestSurface_Clear(t *testing.T) {