feat(templ): add support for --from-list flag and related tests

cmd/relspec/testhelpers_test.go

@@ -110,6 +110,45 @@ func restoreConvertState(s convertState) {
 	convertFlattenSchema = s.flattenSchema
 }
 
+// templState captures and restores all templ global vars.
+type templState struct {
+	sourceType      string
+	sourcePath      string
+	sourceConn      string
+	fromList        []string
+	templatePath    string
+	outputPath      string
+	schemaFilter    string
+	mode            string
+	filenamePattern string
+}
+
+func saveTemplState() templState {
+	return templState{
+		sourceType:      templSourceType,
+		sourcePath:      templSourcePath,
+		sourceConn:      templSourceConn,
+		fromList:        templFromList,
+		templatePath:    templTemplatePath,
+		outputPath:      templOutputPath,
+		schemaFilter:    templSchemaFilter,
+		mode:            templMode,
+		filenamePattern: templFilenamePattern,
+	}
+}
+
+func restoreTemplState(s templState) {
+	templSourceType = s.sourceType
+	templSourcePath = s.sourcePath
+	templSourceConn = s.sourceConn
+	templFromList = s.fromList
+	templTemplatePath = s.templatePath
+	templOutputPath = s.outputPath
+	templSchemaFilter = s.schemaFilter
+	templMode = s.mode
+	templFilenamePattern = s.filenamePattern
+}
+
 // mergeState captures and restores all merge global vars.
 type mergeState struct {
 	targetType    string