Add a simple test for a "manifest.Parse" error

Author: tianon

manifest/parse_test.go

@@ -0,0 +1,20 @@
+package manifest_test
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/docker-library/go-dockerlibrary/manifest"
+)
+
+func TestParseError(t *testing.T) {
+	invalidManifest := `this is just completely bogus and invalid no matter how you slice it`
+
+	man, err := manifest.Parse(strings.NewReader(invalidManifest))
+	if err == nil {
+		t.Errorf("Expected error, got valid manifest instead:\n%s", man)
+	}
+	if !strings.HasPrefix(err.Error(), "cannot parse manifest in either format:") {
+		t.Errorf("Unexpected error: %v", err)
+	}
+}