Mercurial > hg > Members > tatsuki > functionaljava-master > core

comparison src/test/java/fj/data/TestRngState.java @ 0:fe80c1edf1be

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add getLoop
author tatsuki
date Fri, 20 Mar 2015 21:04:03 +0900
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-1:000000000000 0:fe80c1edf1be
1 package fj.data;
2
3 import fj.*;
4 import fj.test.Arbitrary;
5 import fj.test.Coarbitrary;
6 import fj.test.Gen;
7 import fj.test.Property;
8 import org.junit.Assert;
9 import org.junit.Test;
10
11 import static fj.data.Option.some;
12 import static fj.data.Stream.unfold;
13 import static fj.data.test.PropertyAssert.assertResult;
14 import static fj.test.Arbitrary.*;
15 import static fj.test.Coarbitrary.coarbInteger;
16 import static fj.test.Property.prop;
17 import static fj.test.Property.property;
18 import static fj.test.Variant.variant;
19
20 /**
21 * Created by mperry on 4/08/2014.
22 */
23 public class TestRngState {
24
25 static String expected1 = "<4,4,2,2,2,5,3,3,1,5>";
26 static int size = 10;
27
28 static Rng defaultRng() {
29 return new LcgRng(1);
30 }
31
32 static P2<Rng, Integer> num(Rng r) {
33 return r.range(1, 5);
34 }
35
36 static State<Rng, Integer> defaultState() {
37 return State.unit(s -> num(s));
38 }
39
40 static F<State<Rng, Integer>, State<Rng, Integer>> nextState() {
41 return s -> s.mapState(p2 -> num(p2._1()));
42 }
43
44 static P2<Rng, Integer> num(Rng r, int x) {
45 return r.range(x, x + 1);
46 }
47
48 @Test
49 public void testUnfold() {
50 Stream<Integer> s = unfold(r -> some(num(r).swap()), defaultRng());
51 Assert.assertTrue(s.take(size).toList().toString().equals(expected1));
52 }
53
54 @Test
55 public void testTransitions() {
56 P2<List<State<Rng, Integer>>, State<Rng, Integer>> p = List.replicate(size, nextState()).foldLeft(
57 (P2<List<State<Rng, Integer>>, State<Rng, Integer>> p2, F<State<Rng, Integer>, State<Rng, Integer>> f) -> {
58 State<Rng, Integer> s = f.f(p2._2());
59 return P.p(p2._1().snoc(p2._2()), s);
60 }
61 , P.p(List.nil(), defaultState())
62 );
63 List<Integer> ints = p._1().map(s -> s.eval(defaultRng()));
64 Assert.assertTrue(ints.toString().equals(expected1));
65 }
66
67 @Test
68 public void testSequence() {
69 List<Integer> list = State.sequence(List.replicate(size, defaultState())).eval(defaultRng());
70 Assert.assertTrue(list.toString().equals(expected1));
71 }
72
73 @Test
74 public void testTraverse() {
75 List<Integer> list = State.traverse(List.range(1, 10), a -> (State.unit((Rng s) -> num(s, a)))).eval(defaultRng());
76 // System.out.println(list.toString());
77 String expected = "<1,2,3,5,6,7,7,9,10>";
78 Assert.assertTrue(list.toString().equals(expected));
79 }
80
81 public static Arbitrary<State<LcgRng, Integer>> arbState() {
82 return Arbitrary.arbState(Arbitrary.arbLcgRng(), Coarbitrary.coarbLcgRng(), arbInteger);
83 }
84
85 public static Arbitrary<F<LcgRng, P2<LcgRng, Integer>>> arbStateF() {
86 return arbF(Coarbitrary.coarbLcgRng(), arbP2(arbLcgRng(), arbInteger));
87 }
88
89 public static Coarbitrary<State<LcgRng, Integer>> coarbState() {
90 return Coarbitrary.coarbState(Arbitrary.arbLcgRng(), (LcgRng s, Integer j) -> (long) (j >= 0 ? 2 * j : -2 * j + 1));
91 }
92
93 public static Arbitrary<F<Integer, State<LcgRng, Integer>>> arbBindable() {
94 return arbF(coarbInteger, arbState());
95 }
96
97 // Left identity: return i >>= f == f i
98 @Test
99 public void testLeftIdentity() {
100 Property p = property(
101 arbBindable(),
102 arbInteger,
103 arbLcgRng(),
104 (f, i, r) -> {
105 int a = State.<LcgRng, Integer>constant(i).flatMap(f).eval(r);
106 int b = f.f(i).eval(r);
107 // System.out.println(String.format("a=%d, b=%d", a, b));
108 return prop(a == b);
109 }
110 );
111 assertResult(p);
112 }
113
114
115 // Right identity: m >>= return == m
116 @Test
117 public void testRightIdentity() {
118 Property p = Property.property(
119 arbState(),
120 arbLcgRng(),
121 (s, r) -> {
122 int x = s.flatMap(a -> State.constant(a)).eval(r);
123 int y = s.eval(r);
124 // System.out.println(String.format("x=%d, y=%d", x, y));
125 return prop(x == y);
126 }
127 );
128 assertResult(p);
129 }
130
131 // Associativity: (m >>= f) >>= g == m >>= (\x -> f x >>= g)
132 @Test
133 public void testAssociativity() {
134 Property p = Property.property(
135 arbState(),
136 arbBindable(),
137 arbBindable(),
138 arbLcgRng(),
139 (s, f, g, r) -> {
140 int t = s.flatMap(f).flatMap(g).eval(r);
141 int u = s.flatMap(x -> f.f(x).flatMap(g)).eval(r);
142 // System.out.println(String.format("x=%d, y=%d", t, u));
143 return prop(t == u);
144 });
145 assertResult(p);
146 }
147
148
149 }