Add tests

config_test.go

@@ -122,3 +122,43 @@ func TestStringConfig(t *testing.T) {
 	assert.Equal(t, config2.GetRotate(), 1.0)
 	assert.Equal(t, config2.GetColor(), color.White)
 }
+
+func TestFirstRectangleConfig(t *testing.T) {
+	config1 := getFirstRectangleConfig()
+	assert.Equal(t, config1, RectangleConfig{})
+
+	config2 := getFirstRectangleConfig(config1)
+	assert.Equal(t, config2, config1)
+}
+
+func TestFirstCircleConfig(t *testing.T) {
+	config1 := getFirstCircleConfig()
+	assert.Equal(t, config1, CircleConfig{})
+
+	config2 := getFirstCircleConfig(config1)
+	assert.Equal(t, config2, config1)
+}
+
+func TestFirstLineConfig(t *testing.T) {
+	config1 := getFirstLineConfig()
+	assert.Equal(t, config1, LineConfig{})
+
+	config2 := getFirstLineConfig(config1)
+	assert.Equal(t, config2, config1)
+}
+
+func TestFirstPathConfig(t *testing.T) {
+	config1 := getFirstPathConfig()
+	assert.Equal(t, config1, PathConfig{})
+
+	config2 := getFirstPathConfig(config1)
+	assert.Equal(t, config2, config1)
+}
+
+func TestFirstStringConfig(t *testing.T) {
+	config1 := getFirstStringConfig()
+	assert.Equal(t, config1, StringConfig{})
+
+	config2 := getFirstStringConfig(config1)
+	assert.Equal(t, config2, config1)
+}

gridder.go

@@ -69,11 +69,7 @@ func (g *Gridder) DrawRectangle(row int, column int, rectangleConfigs ...Rectang
 		return err
 	}
 
-	center, err := g.getCellCenter(row, column)
-	if err != nil {
-		return err
-	}
-
+	center := g.getCellCenter(row, column)
 	rectangleConfig := getFirstRectangleConfig(rectangleConfigs...)
 	rectangleWidth := rectangleConfig.GetWidth()
 	rectangleHeight := rectangleConfig.GetHeight()
@@ -102,11 +98,7 @@ func (g *Gridder) DrawCircle(row int, column int, circleConfigs ...CircleConfig)
 		return err
 	}
 
-	center, err := g.getCellCenter(row, column)
-	if err != nil {
-		return err
-	}
-
+	center := g.getCellCenter(row, column)
 	circleConfig := getFirstCircleConfig(circleConfigs...)
 
 	g.ctx.Push()
@@ -134,16 +126,8 @@ func (g *Gridder) DrawPath(row1 int, column1 int, row2 int, column2 int, pathCon
 		return err
 	}
 
-	center1, err := g.getCellCenter(row1, column1)
-	if err != nil {
-		return err
-	}
-
-	center2, err := g.getCellCenter(row2, column2)
-	if err != nil {
-		return err
-	}
-
+	center1 := g.getCellCenter(row1, column1)
+	center2 := g.getCellCenter(row2, column2)
 	pathConfig := getFirstPathConfig(pathConfigs...)
 
 	g.ctx.Push()
@@ -168,11 +152,7 @@ func (g *Gridder) DrawLine(row int, column int, lineConfigs ...LineConfig) error
 		return err
 	}
 
-	center, err := g.getCellCenter(row, column)
-	if err != nil {
-		return err
-	}
-
+	center := g.getCellCenter(row, column)
 	lineConfig := getFirstLineConfig(lineConfigs...)
 	length := lineConfig.GetLength()
 
@@ -203,11 +183,7 @@ func (g *Gridder) DrawString(row int, column int, text string, fontFace font.Fac
 		return err
 	}
 
-	center, err := g.getCellCenter(row, column)
-	if err != nil {
-		return err
-	}
-
+	center := g.getCellCenter(row, column)
 	stringConfig := getFirstStringConfig(stringConfigs...)
 	g.ctx.Push()
 	g.ctx.SetFontFace(fontFace)
@@ -302,7 +278,7 @@ func (g *Gridder) getGridDimensions() (float64, float64) {
 	return gridWidth, gridHeight
 }
 
-func (g *Gridder) getCellCenter(row, column int) (*gg.Point, error) {
+func (g *Gridder) getCellCenter(row, column int) *gg.Point {
 	columns := float64(g.gridConfig.GetColumns())
 	rows := float64(g.gridConfig.GetRows())
 
@@ -311,7 +287,7 @@ func (g *Gridder) getCellCenter(row, column int) (*gg.Point, error) {
 
 	x := float64(column)*(gridWidth/columns) + cellWidth/2
 	y := float64(row)*(gridHeight/rows) + cellHeight/2
-	return &gg.Point{X: x, Y: y}, nil
+	return &gg.Point{X: x, Y: y}
 }
 
 func (g *Gridder) verifyInBounds(row, column int) error {

gridder_test.go

@@ -0,0 +1,98 @@
+package gridder
+
+import (
+	"image/color"
+	"testing"
+
+	"github.com/golang/freetype/truetype"
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/image/font/gofont/goregular"
+)
+
+func TestNew(t *testing.T) {
+	_, err := New(ImageConfig{}, GridConfig{Rows: 0})
+	assert.NotNil(t, err)
+
+	_, err = New(ImageConfig{}, GridConfig{Rows: 10, Columns: 0})
+	assert.NotNil(t, err)
+
+	_, err = New(ImageConfig{}, GridConfig{Rows: 10, Columns: 10})
+	assert.Nil(t, err)
+}
+
+func TestPaintCell(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.PaintCell(-1, -1, color.Black)
+	assert.NotNil(t, err)
+
+	err = gridder.PaintCell(0, 0, color.Black)
+	assert.Nil(t, err)
+}
+
+func TestDrawCircle(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.DrawCircle(-1, -1)
+	assert.NotNil(t, err)
+
+	err = gridder.DrawCircle(0, 0)
+	assert.Nil(t, err)
+}
+
+func TestDrawRectangle(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.DrawRectangle(-1, -1)
+	assert.NotNil(t, err)
+
+	err = gridder.DrawRectangle(0, 0)
+	assert.Nil(t, err)
+}
+
+func TestDrawLine(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.DrawLine(-1, -1)
+	assert.NotNil(t, err)
+
+	err = gridder.DrawLine(0, 0)
+	assert.Nil(t, err)
+}
+
+func TestDrawPath(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.DrawPath(-1, -1, -1, -1)
+	assert.NotNil(t, err)
+
+	err = gridder.DrawPath(0, 0, 0, 0)
+	assert.Nil(t, err)
+}
+
+func TestDrawString(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	font, _ := truetype.Parse(goregular.TTF)
+	fontFace := truetype.NewFace(font, &truetype.Options{Size: 24})
+
+	err = gridder.DrawString(-1, -1, "Test", fontFace)
+	assert.NotNil(t, err)
+
+	err = gridder.DrawString(0, 0, "Test", fontFace)
+	assert.Nil(t, err)
+}
+
+func TestSave(t *testing.T) {
+	gridder, err := New(ImageConfig{}, GridConfig{Rows: 1, Columns: 1})
+	assert.Nil(t, err)
+
+	err = gridder.SavePNG()
+	assert.NotNil(t, err)
+}