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Add TreeZipper tests
Signed-off-by: Gábor Lipták <gliptak@gmail.com>
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5 files changed

+117
-4
lines changed

5 files changed

+117
-4
lines changed

‎core/src/main/java/fj/Equal.java‎

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Original file line numberDiff line numberDiff line change
@@ -3,6 +3,7 @@
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import fj.data.*;
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import fj.data.hamt.BitSet;
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import fj.data.hlist.HList;
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import fj.data.optic.Traversal;
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import fj.data.vector.V2;
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import fj.data.vector.V3;
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import fj.data.vector.V4;
@@ -466,6 +467,25 @@ public static <A> Equal<Zipper<A>> zipperEqual(final Equal<A> ea) {
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}
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/**
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* An equal instance for the {@link TreeZipper} type.
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*
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* @param ea Equality across the elements of the tree zipper.
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* @return An equal instance for the {@link TreeZipper} type.
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*/
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public static <A> Equal<TreeZipper<A>> treeZipperEqual(final Equal<A> ea) {
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final Equal<Tree<A>> te = Equal.treeEqual(ea);
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final Equal<Stream<Tree<A>>> st = streamEqual(Equal.treeEqual(ea));
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final Equal<Stream<P3<Stream<Tree<A>>, A, Stream<Tree<A>>>>> sp =
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streamEqual(p3Equal(streamEqual(treeEqual(ea)), ea, streamEqual(treeEqual(ea))));
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return equalDef((a1, a2) ->
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te.eq(a1.focus(), a2.focus()) &&
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st.eq(a1.lefts(), a2.lefts()) &&
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st.eq(a1.rights(), a2.rights()) &&
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sp.eq(a1.parents(), a2.parents())
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);
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}
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/**
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* An equal instance for the {@link Array} type.
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*
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* @param ea Equality across the elements of the array.

‎core/src/main/java/fj/Hash.java‎

Lines changed: 25 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -302,7 +302,31 @@ public static <A> Hash<Zipper<A>> zipperHash(final Hash<A> ha) {
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});
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}
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/**
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/**
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* A hash instance for the {@link TreeZipper} type.
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*
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* @param ha A hash for the elements of the tree zipper.
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* @return A hash instance for the {@link TreeZipper} type.
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*/
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public static <A> Hash<TreeZipper<A>> treeZipperHash(final Hash<A> ha) {
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Hash<Tree<A>> th = treeHash(ha);
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Hash<Stream<Tree<A>>> sth = streamHash(treeHash(ha));
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Hash<Stream<P3<Stream<Tree<A>>, A, Stream<Tree<A>>>>> tsp =
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streamHash(p3Hash(streamHash(treeHash(ha)), ha, streamHash(treeHash(ha))));
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return hash(as -> {
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final int p = 419;
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int r = 239;
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r = p * r + th.hash(as.focus());
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r = p * r + sth.hash(as.lefts());
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r = p * r + sth.hash(as.rights());
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r = p * r + tsp.hash(as.parents());
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return r;
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});
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}
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/**
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* A hash instance for the {@link Tree} type.
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*
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* @param ha A hash for the elements of the tree.

‎core/src/main/java/fj/data/TreeZipper.java‎

Lines changed: 22 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -54,7 +54,17 @@ private TreeZipper(final Tree<A> tree,
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this.parents = parents;
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}
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/**
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@Override
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public final boolean equals(Object other) {
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return Equal.equals0(TreeZipper.class, this, other, () -> Equal.treeZipperEqual(Equal.anyEqual()));
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}
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@Override
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public final int hashCode() {
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return Hash.treeZipperHash(Hash.<A>anyHash()).hash(this);
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}
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/**
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* Creates a new tree zipper given a currently selected tree, a forest on the left, a forest on the right,
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* and a stream of parent contexts.
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*
@@ -341,8 +351,17 @@ public Stream<Tree<A>> lefts() {
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* @return the right siblings of the currently focused node.
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*/
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public Stream<Tree<A>> rights() {
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return rights;
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}
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return rights;
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}
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/**
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* Returns the parents of the currently focused node.
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*
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* @return the parents of the currently focused node.
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*/
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public Stream<P3<Stream<Tree<A>>, A, Stream<Tree<A>>>> parents() {
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return parents;
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}
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/**
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* Indicates whether the current node is at the top of the tree.

‎core/src/test/java/fj/FFunctionsTest.java‎

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@@ -1,5 +1,7 @@
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package fj;
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import fj.data.Tree;
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import fj.data.TreeZipper;
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import org.junit.Test;
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import static org.hamcrest.core.Is.is;
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import static org.junit.Assert.*;
@@ -22,4 +24,20 @@ public void testApply() {
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F<Integer, Integer> f1 = F2Functions.f(f2, 2);
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assertThat(F1Functions.f(f1, 1).f(), is(36));
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}
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@Test
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public void testTreeK() {
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final Tree<Integer> t1 = F1Functions.<Integer, Integer>treeK(Function.identity()).f(1);
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final Tree<Integer> t2 = F1Functions.<Integer, Integer>treeK(Function.identity()).f(2);
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assertThat(F1Functions.<Integer, Integer>mapTree(i -> i + 1).f(t1),
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is(F1Functions.<Integer, Integer>mapTree(i -> i * 1).f(t2)));
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}
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@Test
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public void testTreeZipperK() {
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final TreeZipper<Integer> tz1 = F1Functions.<Integer, Integer>treeZipperK(Function.identity()).f(1);
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final TreeZipper<Integer> tz2 = F1Functions.<Integer, Integer>treeZipperK(Function.identity()).f(2);
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assertThat(F1Functions.<Integer, Integer>mapTreeZipper(i -> i + 1).f(tz1),
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is(F1Functions.<Integer, Integer>mapTreeZipper(i -> i * 1).f(tz2)));
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}
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}

‎core/src/test/java/fj/data/TreeZipperTest.java‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,32 @@
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package fj.data;
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import org.junit.Test;
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import static fj.data.Option.none;
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import static org.hamcrest.core.Is.is;
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import static org.junit.Assert.assertThat;
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public class TreeZipperTest {
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@Test
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public void testDelete() {
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final Tree<Integer> t = Tree.node(1, List.single(Tree.leaf(2)));
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final TreeZipper<Integer> tz = TreeZipper.fromTree(t);
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assertThat(tz.delete(), is(none()));
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}
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@Test
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public void testDeleteForest() {
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final Tree<Integer> t = Tree.node(1, List.single(Tree.leaf(2)));
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final TreeZipper<Integer> tz = TreeZipper.fromForest(Stream.single(t)).some();
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assertThat(tz.delete(), is(none()));
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}
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@Test
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public void testHash() {
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final Tree<Integer> t = Tree.node(1, List.single(Tree.leaf(2)));
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final TreeZipper<Integer> tz1 = TreeZipper.fromForest(Stream.single(t)).some();
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final TreeZipper<Integer> tz2 = TreeZipper.fromForest(Stream.single(t)).some();
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assertThat(tz1.hashCode(), is(tz2.hashCode()));
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}
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}

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