Added StringEvaluator for evaluating string input #1266 (#1278)

pkg/yqlib/string_evaluator_test.go

@@ -0,0 +1,30 @@
+package yqlib
+
+import (
+	"testing"
+
+	"github.com/mikefarah/yq/v4/test"
+)
+
+func TestStringEvaluator_Evaluate_Nominal(t *testing.T) {
+	expected_output := `` +
+		`yq` + "\n" +
+		`---` + "\n" +
+		`jq` + "\n"
+	expression := ".[].name"
+	input := `` +
+		` - name: yq` + "\n" +
+		`   description: yq is a portable command-line YAML, JSON and XML processor` + "\n" +
+		`---` + "\n" +
+		` - name: jq` + "\n" +
+		`   description: Command-line JSON processor` + "\n"
+	encoder := NewYamlEncoder(2, true, true, true)
+	decoder := NewYamlDecoder()
+
+	result, err := NewStringEvaluator().Evaluate(expression, input, encoder, true, decoder)
+	if err != nil {
+		t.Error(err)
+	}
+
+	test.AssertResult(t, expected_output, result)
+}