Strings

vm/vm_test.go

@@ -55,6 +55,12 @@ func testExpectedObject(t *testing.T, expected interface{}, actual object.Object
 			t.Errorf("testBooleanObject failed: %s", err)
 		}
 
+	case string:
+		err := testStringObject(expected, actual)
+		if err != nil {
+			t.Errorf("testStringObject failed: %s", err)
+		}
+
 	case *object.Null:
 		if actual != Null {
 			t.Errorf("object is not Null: %T (%+v)", actual, actual)
@@ -68,7 +74,7 @@ func parse(input string) *ast.Program {
 	return p.ParseProgram()
 }
 
-func testIntegerObject(expected int64, actual object.Object) interface{} {
+func testIntegerObject(expected int64, actual object.Object) error {
 	result, ok := actual.(*object.Integer)
 	if !ok {
 		return fmt.Errorf("object is not Integer. got=%T (%+v", actual, actual)
@@ -81,7 +87,7 @@ func testIntegerObject(expected int64, actual object.Object) interface{} {
 	return nil
 }
 
-func testBooleanObject(expected bool, actual object.Object) interface{} {
+func testBooleanObject(expected bool, actual object.Object) error {
 	result, ok := actual.(*object.Boolean)
 	if !ok {
 		return fmt.Errorf("object is not Boolean. got=%T (%+v", actual, actual)
@@ -94,6 +100,19 @@ func testBooleanObject(expected bool, actual object.Object) interface{} {
 	return nil
 }
 
+func testStringObject(expected string, actual object.Object) error {
+	result, ok := actual.(*object.String)
+	if !ok {
+		return fmt.Errorf("object is not String. got=%T (%+v", actual, actual)
+	}
+
+	if result.Value != expected {
+		return fmt.Errorf("object has wrong value. got=%q, want=%q", result.Value, expected)
+	}
+
+	return nil
+}
+
 func TestIntegerArithmetic(t *testing.T) {
 	tests := []vmTestCase{
 		{"1", 1},
@@ -175,3 +194,13 @@ func TestGlobalLetStatements(t *testing.T) {
 
 	runVmTests(t, tests)
 }
+
+func TestStringExpressions(t *testing.T) {
+	tests := []vmTestCase{
+		{`"monkey"`, "monkey"},
+		{`"mon" + "key"`, "monkey"},
+		{`"mon" + "key" + "banana"`, "monkeybanana"},
+	}
+
+	runVmTests(t, tests)
+}