Introduce AbstractOrderedIterableAssert (#17)

Introduce AbstractOrderedIterableAssert and the corresponding ListIterable and StackIterable assertion types. Overhauling how RichIterable tests are parameterized.

Author: mattbertolini

src/main/java/org/assertj/eclipse/collections/api/AbstractOrderedIterableAssert.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2025-2026 the original author or authors.
+ *
+ * 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
+ *
+ * https://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.assertj.eclipse.collections.api;
+
+import org.assertj.core.api.AbstractAssert;
+import org.assertj.core.api.InstanceOfAssertFactory;
+import org.eclipse.collections.api.ordered.OrderedIterable;
+
+//@format:off
+public abstract class AbstractOrderedIterableAssert<SELF extends AbstractOrderedIterableAssert<SELF, ACTUAL, ELEMENT, ELEMENT_ASSERT>,
+  ACTUAL extends OrderedIterable<? extends ELEMENT>,
+  ELEMENT,
+  ELEMENT_ASSERT extends AbstractAssert<? extends ELEMENT_ASSERT, ELEMENT>>
+  extends AbstractRichIterableAssert<SELF, ACTUAL, ELEMENT, ELEMENT_ASSERT> {
+//@format:on
+
+  protected AbstractOrderedIterableAssert(ACTUAL actual, Class<?> selfType) {
+    super(actual, selfType);
+  }
+
+  @Override
+  public ELEMENT_ASSERT first() {
+    return executeAssertionNavigation(this::internalFirst, () -> nullElementNavigationAssert("check first element"));
+  }
+
+  @Override
+  public <ASSERT extends AbstractAssert<?, ?>> ASSERT first(InstanceOfAssertFactory<?, ASSERT> assertFactory) {
+    return executeAssertionNavigation(() -> internalFirst().asInstanceOf(assertFactory),
+      () -> nullValueAssert(assertFactory));
+  }
+
+  @Override
+  public ELEMENT_ASSERT last() {
+    return executeAssertionNavigation(this::internalLast, () -> nullElementNavigationAssert("check last element"));
+  }
+
+  @Override
+  public <ASSERT extends AbstractAssert<?, ?>> ASSERT last(InstanceOfAssertFactory<?, ASSERT> assertFactory) {
+    return executeAssertionNavigation(() -> internalLast().asInstanceOf(assertFactory),
+      () -> nullValueAssert(assertFactory));
+  }
+
+  private ELEMENT_ASSERT internalFirst() {
+    isNotEmpty();
+    return toAssert(actual.getFirst(), navigationDescription("check first element"));
+  }
+
+  private ELEMENT_ASSERT internalLast() {
+    isNotEmpty();
+    return toAssert(actual.getLast(), navigationDescription("check last element"));
+  }
+
+  // TODO: Decide where this method should live: here, in AbstractRichIterableAssert, or somewhere else
+  protected ELEMENT_ASSERT nullElementNavigationAssert(String description) {
+    return toAssert(null, navigationDescription(description));
+  }
+}

src/main/java/org/assertj/eclipse/collections/api/Assertions.java

@@ -17,8 +17,10 @@
 
 import org.assertj.core.annotation.CheckReturnValue;
 import org.eclipse.collections.api.bag.Bag;
+import org.eclipse.collections.api.list.ListIterable;
 import org.eclipse.collections.api.multimap.Multimap;
 import org.eclipse.collections.api.set.SetIterable;
+import org.eclipse.collections.api.stack.StackIterable;
 
 /**
  * Entry point for assertion methods for the Eclipse Collections library. Each method in this class is a static factory
@@ -44,6 +46,10 @@ public static <T> BagAssert<T> assertThat(Bag<T> actual) {
     return new BagAssert<>(actual);
   }
 
+  public static <T> ListIterableAssert<T> assertThat(ListIterable<T> actual) {
+    return new ListIterableAssert<>(actual);
+  }
+
   /**
    * Creates a new instance of {@link MultimapAssert}.
    *
@@ -63,7 +69,11 @@ public static <KEY, VALUE> MultimapAssert<KEY, VALUE> assertThat(Multimap<KEY, V
    * @return the created assertion object.
    * @param <T> The type of the elements in the set
    */
-  public static <T>SetIterableAssert<T> assertThat(SetIterable<T> actual) {
+  public static <T> SetIterableAssert<T> assertThat(SetIterable<T> actual) {
     return new SetIterableAssert<>(actual);
   }
+
+  public static <T> StackIterableAssert<T> assertThat(StackIterable<T> actual) {
+    return new StackIterableAssert<>(actual);
+  }
 }

src/main/java/org/assertj/eclipse/collections/api/BDDAssertions.java

@@ -17,8 +17,10 @@
 
 import org.assertj.core.annotation.CheckReturnValue;
 import org.eclipse.collections.api.bag.Bag;
+import org.eclipse.collections.api.list.ListIterable;
 import org.eclipse.collections.api.multimap.Multimap;
 import org.eclipse.collections.api.set.SetIterable;
+import org.eclipse.collections.api.stack.StackIterable;
 
 /**
  * Behavior-driven development style entry point for assertion methods for the Eclipse Collections library. Each method
@@ -37,13 +39,24 @@ protected BDDAssertions() {
    * Creates a new instance of {@link BagAssert}.
    *
    * @param actual the actual value.
-   * @return thre created assertion object.
-   * @param <T> THe type of the elements in the bag
+   * @return the created assertion object.
+   * @param <T> The type of the elements in the bag
    */
   public static <T> BagAssert<T> then(Bag<T> actual) {
     return assertThat(actual);
   }
 
+  /**
+   * Creates a new instance of {@link ListIterableAssert}.
+   *
+   * @param actual the actual value.
+   * @return the created assertion object.
+   * @param <T> The type of the elements in the list
+   */
+  public static <T> ListIterableAssert<T> then(ListIterable<T> actual) {
+    return assertThat(actual);
+  }
+
   /**
    * Creates a new instance of {@link MultimapAssert}.
    *
@@ -66,4 +79,15 @@ public static <KEY, VALUE> MultimapAssert<KEY, VALUE> then(Multimap<KEY, VALUE>
   public static <T> SetIterableAssert<T> then(SetIterable<T> actual) {
     return assertThat(actual);
   }
+
+  /**
+   * Creates a new instance of {@link StackIterableAssert}.
+   *
+   * @param actual the actual value.
+   * @return the created assertion object.
+   * @param <T> The type of the elements in the stack
+   */
+  public static <T> StackIterableAssert<T> then(StackIterable<T> actual) {
+    return assertThat(actual);
+  }
 }

src/main/java/org/assertj/eclipse/collections/api/EclipseCollectionsSoftAssertionsProvider.java

@@ -18,8 +18,10 @@
 import org.assertj.core.annotation.CheckReturnValue;
 import org.assertj.core.api.SoftAssertionsProvider;
 import org.eclipse.collections.api.bag.Bag;
+import org.eclipse.collections.api.list.ListIterable;
 import org.eclipse.collections.api.multimap.Multimap;
 import org.eclipse.collections.api.set.SetIterable;
+import org.eclipse.collections.api.stack.StackIterable;
 
 /**
  * Soft assertions implementations for Eclipse Collections types.
@@ -39,6 +41,18 @@ default <T> BagAssert<T> assertThat(Bag<T> actual) {
     return this.proxy(BagAssert.class, Bag.class, actual);
   }
 
+  /**
+   * Creates a new, proxied instance of a {@link ListIterableAssert}
+   *
+   * @param actual the actual value
+   * @return the created assertion object
+   * @param <T> The type of the elements in the list
+   */
+  @SuppressWarnings("unchecked")
+  default <T> ListIterableAssert<T> assertThat(ListIterable<T> actual) {
+    return this.proxy(ListIterableAssert.class, ListIterable.class, actual);
+  }
+
   /**
    * Creates a new, proxied instance of a {@link MultimapAssert}
    *
@@ -63,4 +77,16 @@ default <KEY, VALUE> MultimapAssert<KEY, VALUE> assertThat(Multimap<KEY, VALUE>
   default <T> SetIterableAssert<T> assertThat(SetIterable<T> actual) {
     return this.proxy(SetIterableAssert.class, SetIterable.class, actual);
   }
+
+  /**
+   * Creates a new, proxied instance of a {@link StackIterableAssert}
+   *
+   * @param actual the actual value
+   * @return the created assertion object
+   * @param <T> The type of the elements in the stack
+   */
+  @SuppressWarnings("unchecked")
+  default <T> StackIterableAssert<T> assertThat(StackIterable<T> actual) {
+    return this.proxy(StackIterableAssert.class, StackIterable.class, actual);
+  }
 }

src/main/java/org/assertj/eclipse/collections/api/ListIterableAssert.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright 2025-2026 the original author or authors.
+ *
+ * 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
+ *
+ * https://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.assertj.eclipse.collections.api;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import org.assertj.core.api.AbstractAssert;
+import org.assertj.core.api.InstanceOfAssertFactory;
+import org.assertj.core.api.ObjectAssert;
+import org.eclipse.collections.api.factory.Lists;
+import org.eclipse.collections.api.list.ImmutableList;
+import org.eclipse.collections.api.list.ListIterable;
+
+/**
+ * Assertion methods for {@link ListIterable} interface.
+ *
+ * @param <ELEMENT> the type of elements stored in {@link ListIterable}.
+ */
+public class ListIterableAssert<ELEMENT> extends AbstractOrderedIterableAssert<ListIterableAssert<ELEMENT>, ListIterable<? extends ELEMENT>, ELEMENT, ObjectAssert<ELEMENT>> {
+  public ListIterableAssert(ListIterable<? extends ELEMENT> actual) {
+    super(actual, ListIterableAssert.class);
+  }
+
+  @Override
+  protected ObjectAssert<ELEMENT> toAssert(ELEMENT value) {
+    return new ObjectAssert<>(value);
+  }
+
+  @Override
+  protected ListIterableAssert<ELEMENT> newAbstractIterableAssert(Iterable<? extends ELEMENT> iterable) {
+    ImmutableList<? extends ELEMENT> elements = Lists.immutable.ofAll(iterable);
+    return new ListIterableAssert<>(elements);
+  }
+
+  @Override
+  public ObjectAssert<ELEMENT> element(int index) {
+    return executeAssertionNavigation(() -> internalElement(index),
+      () -> nullElementNavigationAssert("element at index " + index));
+  }
+
+  @Override
+  public <ASSERT extends AbstractAssert<?, ?>> ASSERT element(int index, InstanceOfAssertFactory<?, ASSERT> assertFactory) {
+    return executeAssertionNavigation(() -> internalElement(index).asInstanceOf(assertFactory),
+      () -> nullValueAssert(assertFactory));
+  }
+
+  private ObjectAssert<ELEMENT> internalElement(int index) {
+    isNotEmpty();
+    assertThat(index).describedAs(navigationDescription("check index validity"))
+      .isBetween(0, actual.size() - 1);
+    ELEMENT elementAtIndex = actual.get(index);
+
+    return toAssert(elementAtIndex, navigationDescription("element at index " + index));
+  }
+}

src/main/java/org/assertj/eclipse/collections/api/StackIterableAssert.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2025-2026 the original author or authors.
+ *
+ * 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
+ *
+ * https://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.assertj.eclipse.collections.api;
+
+import org.assertj.core.annotation.CheckReturnValue;
+import org.assertj.core.api.ObjectAssert;
+import org.eclipse.collections.api.factory.Stacks;
+import org.eclipse.collections.api.stack.ImmutableStack;
+import org.eclipse.collections.api.stack.StackIterable;
+
+/**
+ * Assertion methods for {@link StackIterable} interface.
+ *
+ * @param <ELEMENT> the type of elements stored in {@link StackIterable}.
+ */
+@CheckReturnValue
+public class StackIterableAssert<ELEMENT> extends AbstractOrderedIterableAssert<StackIterableAssert<ELEMENT>, StackIterable<? extends ELEMENT>, ELEMENT, ObjectAssert<ELEMENT>> {
+  public StackIterableAssert(StackIterable<? extends ELEMENT> actual) {
+    super(actual, StackIterableAssert.class);
+  }
+
+  @Override
+  protected ObjectAssert<ELEMENT> toAssert(ELEMENT value) {
+    return new ObjectAssert<>(value);
+  }
+
+  @Override
+  protected StackIterableAssert<ELEMENT> newAbstractIterableAssert(Iterable<? extends ELEMENT> iterable) {
+    ImmutableStack<? extends ELEMENT> elements = Stacks.immutable.ofAll(iterable);
+    return new StackIterableAssert<>(elements);
+  }
+}

src/test/java/module-info.java

@@ -17,9 +17,10 @@
  * Test module for AssertJ Eclipse Collections
  */
 open module org.assertj.eclipse.collections.test {
-  exports org.assertj.eclipse.collections.api.bag;
+  exports org.assertj.eclipse.collections.api.list;
   exports org.assertj.eclipse.collections.api.multimap;
-  exports org.assertj.eclipse.collections.api.set;
+  exports org.assertj.eclipse.collections.api.richiterable;
+  exports org.assertj.eclipse.collections.api.stack;
 
   requires org.assertj.eclipse.collections;
   requires org.assertj.core;

src/test/java/org/assertj/eclipse/collections/api/list/ListIterableAssert_Element_Test.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2025-2026 the original author or authors.
+ *
+ * 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
+ *
+ * https://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.assertj.eclipse.collections.api.list;
+
+import static org.assertj.core.api.Assertions.assertThatNoException;
+
+import org.assertj.eclipse.collections.api.ListIterableAssert;
+import org.eclipse.collections.api.factory.Lists;
+import org.eclipse.collections.api.list.ImmutableList;
+import org.junit.jupiter.api.Test;
+
+class ListIterableAssert_Element_Test {
+  @Test
+  void passes() {
+    assertThatNoException().isThrownBy(() -> {
+      ImmutableList<String> list = Lists.immutable.of("TOS", "TNG", "DS9", "VOY", "ENT");
+      new ListIterableAssert<>(list).element(2).isEqualTo("DS9");
+    });
+  }
+}