Add ordered Quality of Iterables ordered by a given Comparator, closes #157

confidence-core/src/main/java/org/saynotobugs/confidence/quality/iterable/Ordered.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2023 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.saynotobugs.confidence.quality.iterable;
+
+import org.dmfs.srcless.annotations.staticfactory.StaticFactories;
+import org.saynotobugs.confidence.Assessment;
+import org.saynotobugs.confidence.Quality;
+import org.saynotobugs.confidence.assessment.AllPassed;
+import org.saynotobugs.confidence.assessment.PassIf;
+import org.saynotobugs.confidence.description.Spaced;
+import org.saynotobugs.confidence.description.Text;
+import org.saynotobugs.confidence.description.Value;
+import org.saynotobugs.confidence.quality.composite.QualityComposition;
+
+import java.util.Comparator;
+import java.util.Iterator;
+
+import static org.saynotobugs.confidence.description.LiteralDescription.NEW_LINE;
+
+@StaticFactories(value = "Core", packageName = "org.saynotobugs.confidence.quality")
+public final class Ordered<T> extends QualityComposition<Iterable<T>>
+{
+    /**
+     * A {@link Quality} that describes an {@link Iterable} that iterates elements in the
+     * order imposed by the given {@link Comparator}.
+     */
+    public Ordered(Comparator<? super T> comparator)
+    {
+        this("", comparator);
+    }
+
+    /**
+     * A {@link Quality} that describes an {@link Iterable} that iterates elements in the
+     * order imposed by the given {@link Comparator}.
+     * <p>
+     * This constructor also takes a description of the {@link Comparator}.
+     */
+    public Ordered(String description, Comparator<? super T> comparator)
+    {
+        super(actual -> new AllPassed(new Text("["), NEW_LINE, new Text("]"), () -> new Iterator<Assessment>()
+            {
+                private final Iterator<T> mDelegate = actual.iterator();
+                private T mCurrent = mDelegate.hasNext() ? mDelegate.next() : null;
+                private int mIndex = 0;
+
+                @Override
+                public boolean hasNext()
+                {
+                    return mDelegate.hasNext();
+                }
+
+                @Override
+                public Assessment next()
+                {
+                    T next = mDelegate.next();
+                    Assessment result = new PassIf(comparator.compare(mCurrent, next) <= 0,
+                        new Spaced(
+                            new Text(mIndex + ":"),
+                            new Value(mCurrent),
+                            new Text(">"),
+                            new Text(++mIndex + ":"),
+                            new Value(next)));
+                    mCurrent = next;
+                    return result;
+                }
+            }),
+            new Text("ordered" + (description.isEmpty() ? "" : " " + description)));
+    }
+}

confidence-core/src/test/java/org/saynotobugs/confidence/quality/iterable/OrderedTest.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2023 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.saynotobugs.confidence.quality.iterable;
+
+import org.dmfs.jems2.comparator.By;
+import org.dmfs.jems2.iterable.EmptyIterable;
+import org.dmfs.jems2.iterable.Seq;
+import org.junit.jupiter.api.Test;
+import org.saynotobugs.confidence.quality.composite.AllOf;
+import org.saynotobugs.confidence.test.quality.Fails;
+import org.saynotobugs.confidence.test.quality.HasDescription;
+import org.saynotobugs.confidence.test.quality.Passes;
+
+import static org.saynotobugs.confidence.Assertion.assertThat;
+
+class OrderedTest
+{
+    @Test
+    void test()
+    {
+        assertThat(new Ordered<>(new By<>(String::length)),
+            new AllOf<>(
+                new Passes<>(new Seq<>("1", "2", "3"),
+                    new Seq<>("1", "12", "123"),
+                    new Seq<>("1", "12"),
+                    new Seq<>("1"),
+                    new EmptyIterable<>()),
+                new Fails<>(new Seq<>("123", "12", "1"), "[0: \"123\" > 1: \"12\"\n  1: \"12\" > 2: \"1\"]"),
+                new Fails<>(new Seq<>("1", "2", "12", "1"), "[...\n  2: \"12\" > 3: \"1\"]"),
+                new HasDescription("ordered")
+            )
+        );
+    }
+
+    @Test
+    void testWithDescription()
+    {
+        assertThat(new Ordered<>("by length", new By<>(String::length)),
+            new AllOf<>(
+                new Passes<>(new Seq<>("1", "2", "3"),
+                    new Seq<>("1", "12", "123"),
+                    new Seq<>("1", "12"),
+                    new Seq<>("1"),
+                    new EmptyIterable<>()),
+                new Fails<>(new Seq<>("123", "12", "1"), "[0: \"123\" > 1: \"12\"\n  1: \"12\" > 2: \"1\"]"),
+                new Fails<>(new Seq<>("1", "2", "12", "1"), "[...\n  2: \"12\" > 3: \"1\"]"),
+                new HasDescription("ordered by length")
+            )
+        );
+    }
+}