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comparators_test.go

@@ -0,0 +1,41 @@
+package colorcrop
+
+import (
+	"image/color"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+func TestColorComparators(t *testing.T) {
+	type In struct {
+		color1 color.Color
+		color2 color.Color
+	}
+
+	comparators := []comparator{CmpSquareRGBComponentsDiff, CmpRGBComponentsDiff}
+
+	tests := []struct {
+		in         In
+		out        float64
+		commentary string
+	}{
+		{in: In{color.RGBA{0, 0, 0, 255}, color.RGBA{255, 255, 255, 255}},
+			out:        1.00,
+			commentary: "Difference between black and white colors"},
+		{in: In{color.RGBA{255, 255, 255, 255}, color.RGBA{255, 255, 255, 255}},
+			out:        0.00,
+			commentary: "Difference between same colors"},
+		{in: In{color.RGBA{255, 255, 255, 0}, color.RGBA{255, 255, 255, 255}},
+			out:        0.00,
+			commentary: "Difference between same colors with different transparency"},
+	}
+
+	for _, comparator := range comparators {
+		for _, test := range tests {
+			if CmpSquareRGBComponentsDiff(test.in.color2, test.in.color1) != test.out {
+				t.Errorf("%s: %s: expected %.2f, got %.2f", runtime.FuncForPC(reflect.ValueOf(comparator).Pointer()).Name(), test.commentary, test.out, CmpSquareRGBComponentsDiff(test.in.color2, test.in.color1))
+			}
+		}
+	}
+}