Config variables reader

Fixes: 182330871
Test: go test config_variables_test.go
Change-Id: I89240fb0f1900172cb4d62057c86907bb9a1f58f

mk2rbc/config_variables_test.go

@@ -0,0 +1,60 @@
+// Copyright 2021 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mk2rbc
+
+import (
+	"path/filepath"
+	"reflect"
+	"runtime"
+	"testing"
+)
+
+type testVar struct {
+	name string
+	cl   varClass
+	ty   starlarkType
+}
+
+type testVariables struct {
+	v []testVar
+}
+
+func (v *testVariables) NewVariable(name string, varClass varClass, valueType starlarkType) {
+	v.v = append(v.v, testVar{name, varClass, valueType})
+}
+
+// getTestDirectory returns the test directory, which should be the test/ subdirectory
+func getTestDirectory() string {
+	_, myFile, _, _ := runtime.Caller(1)
+	return filepath.Join(filepath.Dir(myFile), "test")
+}
+
+func TestConfigVariables(t *testing.T) {
+	testFile := filepath.Join(getTestDirectory(), "config_variables.mk.test")
+	var actual testVariables
+	if err := FindConfigVariables(testFile, &actual); err != nil {
+		t.Fatal(err)
+	}
+	expected := testVariables{[]testVar{
+		{"PRODUCT_NAME", VarClassConfig, starlarkTypeUnknown},
+		{"PRODUCT_MODEL", VarClassConfig, starlarkTypeUnknown},
+		{"PRODUCT_LOCALES", VarClassConfig, starlarkTypeList},
+		{"PRODUCT_AAPT_CONFIG", VarClassConfig, starlarkTypeList},
+		{"PRODUCT_AAPT_PREF_CONFIG", VarClassConfig, starlarkTypeUnknown},
+	}}
+	if !reflect.DeepEqual(expected, actual) {
+		t.Errorf("\nExpected: %v\n  Actual: %v", expected, actual)
+	}
+}