Added File operators

pkg/yqlib/operator_file_test.go

@@ -0,0 +1,31 @@
+package yqlib
+
+import (
+	"testing"
+)
+
+var fileOperatorScenarios = []expressionScenario{
+	{
+		description: "Get filename",
+		document:    `{}`,
+		expression:  `filename`,
+		expected: []string{
+			"D0, P[], (!!str)::sample.yml\n",
+		},
+	},
+	{
+		description: "Get file index",
+		document:    `{}`,
+		expression:  `fileIndex`,
+		expected: []string{
+			"D0, P[], (!!int)::0\n",
+		},
+	},
+}
+
+func TestFileOperatorsScenarios(t *testing.T) {
+	for _, tt := range fileOperatorScenarios {
+		testScenario(t, &tt)
+	}
+	documentScenarios(t, "File Operators", fileOperatorScenarios)
+}