Allow setting custom file extension for snapshots (#47)

config.go

@@ -66,13 +66,24 @@ func FatalOnMismatch(fatalOnMismatch bool) Configurator {
 	}
 }
 
+// SnapshotFileExtension allows you to change the extension of the snapshot files
+// that are written. E.g. if you're snapshotting HTML then adding SnapshotFileExtension(".html")
+// will allow for more easier viewing of snapshots.
+// Default: "", no extension is added.
+func SnapshotFileExtension(snapshotFileExtension string) Configurator {
+	return func(c *Config) {
+		c.snapshotFileExtension = snapshotFileExtension
+	}
+}
+
 // Config provides the same snapshotting functions with additional configuration capabilities.
 type Config struct {
 	shouldUpdate           func() bool
 	subDirName             string
 	failOnUpdate           bool
 	createNewAutomatically bool
 	fatalOnMismatch        bool
+	snapshotFileExtension  string
 }
 
 // NewDefaultConfig returns a new Config instance initialised with the same options as
@@ -84,6 +95,7 @@ func NewDefaultConfig() *Config {
 		FailOnUpdate(true),
 		CreateNewAutomatically(true),
 		FatalOnMismatch(false),
+		SnapshotFileExtension(""),
 	)
 }
 
@@ -97,5 +109,6 @@ func (c *Config) clone() *Config {
 		failOnUpdate:           c.failOnUpdate,
 		createNewAutomatically: c.createNewAutomatically,
 		fatalOnMismatch:        c.fatalOnMismatch,
+		snapshotFileExtension:  c.snapshotFileExtension,
 	}
 }

examples/.snapshots/TestSnapshotFileExtension.myextension

@@ -0,0 +1 @@
+This should end up in a file with extension .myextension

examples/advanced_test.go

@@ -202,3 +202,8 @@ func TestGlobalFatalOnMismatch(t *testing.T) {
 	mockT.AssertNotCalled(t, "Error", mock.Anything)
 	mockT.AssertCalled(t, "Fatal", mock.Anything)
 }
+
+func TestSnapshotFileExtension(t *testing.T) {
+	snapshotter := cupaloy.New(cupaloy.SnapshotFileExtension(".myextension"))
+	snapshotter.SnapshotT(t, "This should end up in a file with extension .myextension")
+}

util.go

@@ -47,7 +47,7 @@ func envVariableSet(envVariable string) bool {
 }
 
 func (c *Config) snapshotFilePath(testName string) string {
-	return filepath.Join(c.subDirName, testName)
+	return filepath.Join(c.subDirName, testName+c.snapshotFileExtension)
 }
 
 // Legacy snapshot format where all items were spewed
@@ -109,7 +109,7 @@ func (c *Config) updateSnapshot(snapshotName string, snapshot string) error {
 		//TODO: should a warning still be printed here?
 		return nil
 	}
-	
+
 	if isNewSnapshot {
 		return fmt.Errorf("snapshot created for test %s", snapshotName)
 	}