Clarify error when discovery source is invalid

pkg/v1/cli/command/core/discovery_source.go

@@ -229,8 +229,10 @@ func createDiscoverySource(dsType, dsName, uri string) (configv1alpha1.PluginDis
 		pluginDiscoverySource.Local = createLocalDiscoverySource(dsName, uri)
 	case common.DiscoveryTypeOCI:
 		pluginDiscoverySource.OCI = createOCIDiscoverySource(dsName, uri)
-	default:
+	case common.DiscoveryTypeGCP, common.DiscoveryTypeKubernetes, common.DiscoveryTypeREST:
 		return pluginDiscoverySource, errors.Errorf("discovery source type '%s' is not yet supported", dsType)
+	default:
+		return pluginDiscoverySource, errors.Errorf("unknown discovery source type '%s'", dsType)
 	}
 	return pluginDiscoverySource, nil
 }

pkg/v1/cli/command/core/discovery_source_test.go

@@ -44,6 +44,26 @@ func Test_createDiscoverySource(t *testing.T) {
 	assert.NotNil(pd.OCI)
 	assert.Equal(pd.OCI.Name, "fake-oci-discovery-name")
 	assert.Equal(pd.OCI.Image, "test.registry.com/test-image:v1.0.0")
+
+	// When discovery source is gcp
+	_, err = createDiscoverySource("gcp", "fake-discovery-name", "fake/path")
+	assert.NotNil(err)
+	assert.Contains(err.Error(), "not yet supported")
+
+	// When discovery source is kubernetes
+	_, err = createDiscoverySource("kubernetes", "fake-discovery-name", "fake/path")
+	assert.NotNil(err)
+	assert.Contains(err.Error(), "not yet supported")
+
+	// When discovery source is rest
+	_, err = createDiscoverySource("rest", "fake-discovery-name", "fake/path")
+	assert.NotNil(err)
+	assert.Contains(err.Error(), "not yet supported")
+
+	// When discovery source is an unknown value
+	_, err = createDiscoverySource("unexpectedValue", "fake-discovery-name", "fake/path")
+	assert.NotNil(err)
+	assert.Contains(err.Error(), "unknown discovery source type 'unexpectedValue'")
 }
 
 func Test_addDiscoverySource(t *testing.T) {