Add test for sha256sum function

pkg/templatelib/lib_example_test.go

@@ -219,3 +219,17 @@ func Example_getenv() {
 	// BAZ: foobar
 	// FOOBARBAZ
 }
+
+func Example_sha256sum() {
+	tmpl, err := template.New("sha256sum").Funcs(templatelib.FuncMap).Parse(`
+		{{- "Hello World!" | sha256sum -}}
+	`)
+
+	err = tmpl.Execute(os.Stdout, nil)
+	if err != nil {
+		panic(err)
+	}
+
+	// Output:
+	// 7f83b1657ff1fc53b92dc18148a1d65dfc2d4b1fa3d677284addd200126d9069
+}