fix go vet issues

file_test.go

@@ -33,6 +33,6 @@ func TestWrite(t *testing.T) {
 
 	err = Write("fixtures/test_write_out.jpg", buf)
 	if err != nil {
-		t.Fatal("Cannot write the file: %#v", err)
+		t.Fatalf("Cannot write the file: %#v", err)
 	}
 }

metadata_test.go

@@ -56,13 +56,13 @@ func TestMetadata(t *testing.T) {
 			t.Fatalf("Unexpected image orientation: %d != %d", metadata.Orientation, file.orientation)
 		}
 		if metadata.Alpha != file.alpha {
-			t.Fatalf("Unexpected image alpha: %s != ", metadata.Alpha, file.alpha)
+			t.Fatalf("Unexpected image alpha: %v != %v", metadata.Alpha, file.alpha)
 		}
 		if metadata.Profile != file.profile {
-			t.Fatalf("Unexpected image profile: %s != %s", metadata.Profile, file.profile)
+			t.Fatalf("Unexpected image profile: %v != %v", metadata.Profile, file.profile)
 		}
 		if metadata.Space != file.space {
-			t.Fatalf("Unexpected image profile: %s != %s", metadata.Profile, file.profile)
+			t.Fatalf("Unexpected image profile: %v != %v", metadata.Profile, file.profile)
 		}
 	}
 }

resize_test.go

@@ -58,7 +58,7 @@ func TestResizeVerticalImage(t *testing.T) {
 		}
 
 		if DetermineImageType(image) != test.format {
-			t.Fatal("Image format is invalid. Expected: %s", test.format)
+			t.Fatalf("Image format is invalid. Expected: %v", test.format)
 		}
 
 		size, _ := Size(image)
@@ -99,7 +99,7 @@ func TestResizeCustomSizes(t *testing.T) {
 		}
 
 		if DetermineImageType(image) != test.format {
-			t.Fatal("Image format is invalid. Expected: %s", test.format)
+			t.Fatalf("Image format is invalid. Expected: %v", test.format)
 		}
 
 		size, _ := Size(image)