test/frontend/stream_matcher_test.dart

// Copyright (c) 2017, 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 'dart:async';

import 'package:async/async.dart';
import 'package:term_glyph/term_glyph.dart' as glyph;
import 'package:test/test.dart';

import '../utils.dart';

void main() {
  setUpAll(() {
    glyph.ascii = true;
  });

  Stream stream;
  StreamQueue queue;
  Stream errorStream;
  StreamQueue errorQueue;
  setUp(() {
    stream = new Stream.fromIterable([1, 2, 3, 4, 5]);
    queue = new StreamQueue(new Stream.fromIterable([1, 2, 3, 4, 5]));
    errorStream =
        new Stream.fromFuture(new Future.error("oh no!", StackTrace.current));
    errorQueue = new StreamQueue(
        new Stream.fromFuture(new Future.error("oh no!", StackTrace.current)));
  });

  group("emits()", () {
    test("matches the first event of a Stream", () {
      expect(stream, emits(1));
    });

    test("rejects the first event of a Stream", () {
      expect(
          expectLater(stream, emits(2)),
          throwsTestFailure(allOf([
            startsWith("Expected: should emit an event that <2>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n")
          ])));
    });

    test("matches and consumes the next event of a StreamQueue", () {
      expect(queue, emits(1));
      expect(queue.next, completion(equals(2)));
      expect(queue, emits(3));
      expect(queue.next, completion(equals(4)));
    });

    test("rejects and does not consume the first event of a StreamQueue", () {
      expect(
          expectLater(queue, emits(2)),
          throwsTestFailure(allOf([
            startsWith("Expected: should emit an event that <2>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n")
          ])));

      expect(queue, emits(1));
    });

    test("rejects an empty stream", () {
      expect(
          expectLater(new Stream.empty(), emits(1)),
          throwsTestFailure(allOf([
            startsWith("Expected: should emit an event that <1>\n"),
            endsWith("   Which: emitted x Stream closed.\n")
          ])));
    });

    test("forwards a stream error", () {
      expect(expectLater(errorStream, emits(1)), throwsA("oh no!"));
    });

    test("wraps a normal matcher", () {
      expect(queue, emits(lessThan(5)));
      expect(expectLater(queue, emits(greaterThan(5))),
          throwsTestFailure(anything));
    });

    test("returns a StreamMatcher as-is", () {
      expect(queue, emits(emitsThrough(4)));
      expect(queue, emits(5));
    });
  });

  group("emitsDone", () {
    test("succeeds for an empty stream", () {
      expect(new Stream.empty(), emitsDone);
    });

    test("fails for a stream with events", () {
      expect(
          expectLater(stream, emitsDone),
          throwsTestFailure(allOf([
            startsWith("Expected: should be done\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n")
          ])));
    });
  });

  group("emitsError()", () {
    test("consumes a matching error", () {
      expect(errorQueue, emitsError("oh no!"));
      expect(errorQueue.hasNext, completion(isFalse));
    });

    test("fails for a non-matching error", () {
      expect(
          expectLater(errorStream, emitsError("oh heck")),
          throwsTestFailure(allOf([
            startsWith("Expected: should emit an error that 'oh heck'\n"),
            contains("   Which: emitted ! oh no!\n"),
            contains("                  x Stream closed.\n"
                "            which threw 'oh no!'\n"
                "                  stack "),
            endsWith("                  which is different.\n"
                "                        Expected: oh heck\n"
                "                          Actual: oh no!\n"
                "                                     ^\n"
                "                         Differ at offset 3\n")
          ])));
    });

    test("fails for a stream with events", () {
      expect(
          expectLater(stream, emitsDone),
          throwsTestFailure(allOf([
            startsWith("Expected: should be done\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n")
          ])));
    });
  });

  group("mayEmit()", () {
    test("consumes a matching event", () {
      expect(queue, mayEmit(1));
      expect(queue, emits(2));
    });

    test("allows a non-matching event", () {
      expect(queue, mayEmit("fish"));
      expect(queue, emits(1));
    });
  });

  group("emitsAnyOf()", () {
    test("consumes an event that matches a matcher", () {
      expect(queue, emitsAnyOf([2, 1, 3]));
      expect(queue, emits(2));
    });

    test("consumes as many events as possible", () {
      expect(
          queue,
          emitsAnyOf([
            1,
            emitsInOrder([1, 2]),
            emitsInOrder([1, 2, 3])
          ]));

      expect(queue, emits(4));
    });

    test("fails if no matchers match", () {
      expect(
          expectLater(stream, emitsAnyOf([2, 3, 4])),
          throwsTestFailure(allOf([
            startsWith("Expected: should do one of the following:\n"
                "          * emit an event that <2>\n"
                "          * emit an event that <3>\n"
                "          * emit an event that <4>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n"
                "            which failed all options:\n"
                "                  * failed to emit an event that <2>\n"
                "                  * failed to emit an event that <3>\n"
                "                  * failed to emit an event that <4>\n")
          ])));
    });

    test("allows an error if any matcher matches", () {
      expect(errorStream, emitsAnyOf([1, 2, emitsError("oh no!")]));
    });

    test("rethrows an error if no matcher matches", () {
      expect(
          expectLater(errorStream, emitsAnyOf([1, 2, 3])), throwsA("oh no!"));
    });
  });

  group("emitsInOrder()", () {
    test("consumes matching events", () {
      expect(queue, emitsInOrder([1, 2, emitsThrough(4)]));
      expect(queue, emits(5));
    });

    test("fails if the matchers don't match in order", () {
      expect(
          expectLater(queue, emitsInOrder([1, 3, 2])),
          throwsTestFailure(allOf([
            startsWith("Expected: should do the following in order:\n"
                "          * emit an event that <1>\n"
                "          * emit an event that <3>\n"
                "          * emit an event that <2>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n"
                "            which didn't emit an event that <3>\n")
          ])));
    });
  });

  group("emitsThrough()", () {
    test("consumes events including those matching the matcher", () {
      expect(queue, emitsThrough(emitsInOrder([3, 4])));
      expect(queue, emits(5));
    });

    test("consumes the entire queue with emitsDone", () {
      expect(queue, emitsThrough(emitsDone));
      expect(queue.hasNext, completion(isFalse));
    });

    test("fails if the queue never matches the matcher", () {
      expect(
          expectLater(queue, emitsThrough(6)),
          throwsTestFailure(allOf([
            startsWith("Expected: should eventually emit an event that <6>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n"
                "            which never did emit an event that <6>\n")
          ])));
    });
  });

  group("mayEmitMultiple()", () {
    test("consumes multiple instances of the given matcher", () {
      expect(queue, mayEmitMultiple(lessThan(3)));
      expect(queue, emits(3));
    });

    test("consumes zero instances of the given matcher", () {
      expect(queue, mayEmitMultiple(6));
      expect(queue, emits(1));
    });

    test("doesn't rethrow errors", () {
      expect(errorQueue, mayEmitMultiple(1));
      expect(errorQueue, emitsError("oh no!"));
    });
  });

  group("neverEmits()", () {
    test("succeeds if the event never matches", () {
      expect(queue, neverEmits(6));
      expect(queue, emits(1));
    });

    test("fails if the event matches", () {
      expect(
          expectLater(stream, neverEmits(4)),
          throwsTestFailure(allOf([
            startsWith("Expected: should never emit an event that <4>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n"
                "            which after 3 events did emit an event that <4>\n")
          ])));
    });

    test("fails if emitsDone matches", () {
      expect(expectLater(stream, neverEmits(emitsDone)),
          throwsTestFailure(anything));
    });

    test("doesn't rethrow errors", () {
      expect(errorQueue, neverEmits(6));
      expect(errorQueue, emitsError("oh no!"));
    });
  });

  group("emitsInAnyOrder()", () {
    test("consumes events that match in any order", () {
      expect(queue, emitsInAnyOrder([3, 1, 2]));
      expect(queue, emits(4));
    });

    test("fails if the events don't match in any order", () {
      expect(
          expectLater(stream, emitsInAnyOrder([4, 1, 2])),
          throwsTestFailure(allOf([
            startsWith("Expected: should do the following in any order:\n"
                "          * emit an event that <4>\n"
                "          * emit an event that <1>\n"
                "          * emit an event that <2>\n"),
            endsWith("   Which: emitted * 1\n"
                "                  * 2\n"
                "                  * 3\n"
                "                  * 4\n"
                "                  * 5\n"
                "                  x Stream closed.\n")
          ])));
    });

    test("doesn't rethrow if some ordering matches", () {
      expect(errorQueue, emitsInAnyOrder([emitsDone, emitsError("oh no!")]));
    });

    test("rethrows if no ordering matches", () {
      expect(
          expectLater(errorQueue, emitsInAnyOrder([1, emitsError("oh no!")])),
          throwsA("oh no!"));
    });
  });
}