GetVideoFrame test for valid input, invalid path and out-of-range frame index

frame_test.go

@@ -0,0 +1,66 @@
+package vidio
+
+import (
+	"image/png"
+	"os"
+	"testing"
+)
+
+func TestGetFrameShouldReturnErrorOnInvalidFilePath(t *testing.T) {
+	path := "test/koala-video-not-present.mp4"
+
+	frame, err := GetVideoFrame(path, 2)
+
+	if frame != nil {
+		t.Errorf("Frame was expected to be nil")
+	}
+
+	if err == nil {
+		t.Error("Error was expected to not be nil")
+	}
+}
+
+func TestGetFrameShouldReturnErrorOnOutOfRangeFrame(t *testing.T) {
+	path := "test/koala.mp4"
+	framesCount := 101
+
+	frame, err := GetVideoFrame(path, framesCount+1)
+
+	if frame != nil {
+		t.Error("Frames was expected to be nil")
+	}
+
+	if err == nil {
+		t.Error("Error was expected to not be nil")
+	}
+}
+
+func TestGetFrameShouldReturnCorrectFrame(t *testing.T) {
+	path := "test/koala.mp4"
+
+	expectedFrameFile, _ := os.Open("test/koala-frame5.png")
+	defer expectedFrameFile.Close()
+
+	expectedFrame, _ := png.Decode(expectedFrameFile)
+
+	actualFrame, err := GetVideoFrame(path, 5)
+
+	if actualFrame == nil {
+		t.Error("Frame was expected to not be nil")
+	}
+
+	if err != nil {
+		t.Error("Error was expected to be nil")
+	}
+
+	for xIndex := 0; xIndex < expectedFrame.Bounds().Dx(); xIndex += 1 {
+		for yIndex := 0; yIndex < expectedFrame.Bounds().Dy(); yIndex += 1 {
+			eR, eG, eB, eA := expectedFrame.At(xIndex, yIndex).RGBA()
+			aR, aG, aB, aA := actualFrame.At(xIndex, yIndex).RGBA()
+
+			if eR != aR || eG != aG || eB != aB || eA != aA {
+				t.Error("The expected and actual frames were expected to be equal")
+			}
+		}
+	}
+}