Bugfix #64 (#67)

* add test to show the panic manifesting

* fix array index out of bounds panic in mock schema registry client

mockSchemaRegistryClient.go

@@ -106,7 +106,9 @@ func (mck MockSchemaRegistryClient) GetLatestSchema(subject string) (*Schema, er
 	if getSchemaVersionErr != nil {
 		return nil, getSchemaVersionErr
 	}
-
+	if len(versions) == 0 {
+		return nil, errors.New("Subject not found")
+	}
 	latestVersion := versions[len(versions)-1]
 	thisSchema, err := mck.GetSchemaByVersion(subject, latestVersion)
 	if err != nil {

mockSchemaRegistryClient_test.go

@@ -117,6 +117,15 @@ func TestMockSchemaRegistryClient_GetLatestSchema(t *testing.T) {
 	}
 }
 
+func TestMockSchemaRegistryClient_GetLatestSchema_WhenNoSchemaRegistered(t *testing.T) {
+	localClient := CreateMockSchemaRegistryClient("")
+	var err error
+	assert.NotPanics(t, func() {
+		_, err = localClient.GetLatestSchema("some-innexistent-schema-subject")
+	})
+	assert.EqualError(t, err, "Subject not found")
+}
+
 func TestMockSchemaRegistryClient_GetSchemaVersions(t *testing.T) {
 	versions, _ := srClient.GetSchemaVersions("test1-key")
 	assert.Equal(t, 2, len(versions))