test/evaluate_test.dart

// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:test/test.dart';

import 'package:boolean_selector/boolean_selector.dart';

void main() {
  group("operator:", () {
    test("conditional", () {
      _expectEval("true ? true : false", true);
      _expectEval("true ? false : true", false);
      _expectEval("false ? true : false", false);
      _expectEval("false ? false : true", true);
    });

    test("or", () {
      _expectEval("true || true", true);
      _expectEval("true || false", true);
      _expectEval("false || true", true);
      _expectEval("false || false", false);
    });

    test("and", () {
      _expectEval("true && true", true);
      _expectEval("true && false", false);
      _expectEval("false && true", false);
      _expectEval("false && false", false);
    });

    test("not", () {
      _expectEval("!true", false);
      _expectEval("!false", true);
    });
  });

  test("with a semantics function", () {
    _expectEval("foo", false,
        semantics: (String variable) => variable.contains("a"));
    _expectEval("bar", true,
        semantics: (String variable) => variable.contains("a"));
    _expectEval("baz", true,
        semantics: (String variable) => variable.contains("a"));
  });
}

/// Asserts that [expression] evaluates to [result] against [semantics].
///
/// By default, "true" is true and all other variables are "false".
void _expectEval(String expression, bool result, {semantics}) {
  expect(_eval(expression, semantics: semantics), equals(result),
      reason: 'Expected "$expression" to evaluate to $result.');
}

/// Returns the result of evaluating [expression] on [semantics].
///
/// By default, "true" is true and all other variables are "false".
bool _eval(String expression, {semantics}) {
  var selector = BooleanSelector.parse(expression);
  return selector.evaluate(semantics ?? ["true"]);
}