org.dmfs.jems.hamcrest.matchers.GeneratableMatcher Maven / Gradle / Ivy
/*
* Copyright 2018 dmfs GmbH
*
*
* 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 org.dmfs.jems.hamcrest.matchers;
import org.dmfs.jems.iterable.elementary.Seq;
import org.dmfs.jems.generatable.Generatable;
import org.dmfs.jems.generator.Generator;
import org.dmfs.jems.iterable.decorators.Mapped;
import org.hamcrest.CoreMatchers;
import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeDiagnosingMatcher;
/**
* A {@link Matcher} to test {@link Generatable}s for the correct start sequence. Note, due do the infinite nature of a {@link Generatable} it is not possible
* to test all the results.
*
* @author Marten Gajda
*/
public final class GeneratableMatcher extends TypeSafeDiagnosingMatcher>
{
private final Iterable> mExpectedStartSequence;
@SafeVarargs
public static Matcher> startsWith(T... elements)
{
return new GeneratableMatcher<>(new Mapped<>(CoreMatchers::is, new Seq<>(elements)));
}
@SafeVarargs
public static Matcher> startsWith(Matcher... elements)
{
return new GeneratableMatcher<>(new Seq<>(elements));
}
public static Matcher> startsWith(Iterable> elements)
{
return new GeneratableMatcher<>(elements);
}
public GeneratableMatcher(Iterable> expectedStartSequence)
{
mExpectedStartSequence = expectedStartSequence;
}
@Override
protected boolean matchesSafely(Generatable item, Description mismatchDescription)
{
int pos = 0;
Generator generator = item.generator();
for (Matcher matcher : mExpectedStartSequence)
{
T next = generator.next();
if (!matcher.matches(next))
{
mismatchDescription.appendText(String.format("element at position %d ", pos));
matcher.describeMismatch(next, mismatchDescription);
return false;
}
pos += 1;
}
return true;
}
@Override
public void describeTo(Description description)
{
description.appendText("Generatable with start sequence ");
boolean first = true;
for (Matcher matcher : mExpectedStartSequence)
{
if (first)
{
first = false;
}
else
{
description.appendText(", ");
}
matcher.describeTo(description);
}
}
}