1 /*global require, it, assert, assertEqual, assertNot */
2 /*jshint -W085 */ // "Don't use 'with'."
4 var JS
= this.JS
|| require('jstest');
5 var stringLerp
= require('../string-lerp');
7 var HALF_POOS
= /\uD83D\uD83D|\uDCA9\uDCA9|\uD83D$/;
8 var UNUSUAL_Q
= 'q\u0307\u0323';
9 var A
= "Do you like green eggs and ham?";
10 var B
= "I do not like them, Sam-I-am.";
12 function itHandlesBaseCases (parent
, lerp
) { with (parent
) {
13 it("handles empty strings", function () { with (this) {
14 assertEqual("", lerp("", "", -1));
15 assertEqual("", lerp("", "", 0));
16 assertEqual("", lerp("", "", 0.5));
17 assertEqual("", lerp("", "", 1));
18 assertEqual("", lerp("", "", 2));
21 it("maintains identity", function () { with (this) {
22 for (var i
= -1; i
< 2; i
+= 1/1024) {
23 assertEqual(A
, lerp(A
, A
, i
));
24 assertEqual(B
, lerp(B
, B
, i
));
29 function itMakesValidStrings (parent
, lerp
) { with (parent
) {
30 it("doesn't make half a poo", function () { with (this) {
31 var poos
= "\uD83D\uDCA9\uD83D\uDCA9\uD83D\uDCA9\uD83D\uDCA9";
32 assertEqual("\uD83D\uDCA9\uD83D\uDCA9", lerp("", poos
, 0.5));
33 assertEqual("\uD83D\uDCA9", lerp("", poos
, 0.35));
35 for (var i
= 0; i
<= 1; i
+= 1/256)
36 assertNot(lerp("", poos
, i
).match(HALF_POOS
));
39 it("doesn't misplace combining marks", function () { with (this) {
40 for (var i
= 0; i
<= 1; i
+= 1/256) {
41 var r
= lerp("a", UNUSUAL_Q
, i
);
42 assert(r
=== "a" || r
=== UNUSUAL_Q
);
47 function itDoesntOvershoot (parent
, lerp
) { with (parent
) {
48 it("handles lows", function () { with (this) {
49 assertEqual(A
, lerp(A
, B
, -Infinity
));
50 assertEqual(A
, lerp(A
, B
, -1));
51 assertEqual(A
, lerp(A
, B
, 0));
54 it("handles highs", function () { with (this) {
55 assertEqual(B
, lerp(A
, B
, 1));
56 assertEqual(B
, lerp(A
, B
, 2));
57 assertEqual(B
, lerp(A
, B
, Infinity
));
61 JS
.Test
.describe('fast lerp', function () { with (this) {
62 var lerp
= stringLerp
.fastLerp
;
64 itHandlesBaseCases(this, lerp
);
65 itMakesValidStrings(this, lerp
);
66 itDoesntOvershoot(this, lerp
);
68 it("crams strings together", function () { with (this) {
69 assertEqual("I do not ke green eggs and ham?", lerp(A
, B
, 0.3));
70 assertEqual("I do not like tn eggs and ham?", lerp(A
, B
, 0.5));
71 assertEqual("I do not like them, Sam-I-am?", lerp(A
, B
, 0.98));
76 function itEditsHumanly(parent
, lerp
) { with (parent
) {
77 it("edits strings", function () { with (this) {
78 assertEqual(A
, lerp(A
, B
, 0.01));
79 assertEqual("I do not like treen eggs and ham?", lerp(A
, B
, 0.3));
80 assertEqual("I do not like them, eggs and ham?", lerp(A
, B
, 0.5));
81 assertEqual("I do not like them, Sam-Iham?", lerp(A
, B
, 0.9));
82 assertEqual(B
, lerp(A
, B
, 0.99));
85 it("prefers ins/del to sub/sub", function () { with (this) {
86 // When the cost is uniform this string can be transformed by
87 // rewriting the whole thing for the same cost as deleting the
88 // front and adding to the back. But visually, we'd rather do
90 assertEqual("core", lerp("hard core", "core dump", 0.50));
93 it("weights ins/del cheaper than sub", function () { with (this) {
94 // When the cost is uniform it is cheaper to rewrite the
95 // former into the latter. But we'd rather keep the "core" for
96 // visual reasons, so we need to make sure we have unequal
98 assertEqual("core", lerp("apple core", "core dump", 0.51));
102 JS
.Test
.describe('diff lerp', function () { with (this) {
103 var lerp
= stringLerp
.diffLerp
;
105 itHandlesBaseCases(this, lerp
);
106 itMakesValidStrings(this, lerp
);
107 itDoesntOvershoot(this, lerp
);
108 itEditsHumanly(this, lerp
);
111 function itTreatsNumeralsAsNumbers(parent
, lerp
) { with (parent
) {
112 it("handles single numbers", function () { with (this) {
113 assertEqual("0", lerp("0", "100", 0));
114 assertEqual("50", lerp("0", "100", 0.5));
115 assertEqual("100", lerp("0", "100", 1.0));
116 assertEqual("150", lerp("0", "100", 1.5));
119 it("rounds integers", function () { with (this) {
120 assertEqual("12", lerp("0", "100", 0.123));
121 assertEqual("12.3", lerp("0.0", "100.0", 0.123));
122 assertEqual("12.3", lerp("0.0", "100", 0.123));
123 assertEqual("12.3", lerp("0.0", "100.0", 0.123));
126 it("thinks about precision", function () { with (this) {
127 assertEqual("12.30", lerp("0.00", "100.00", 0.123));
128 assertEqual("12.300", lerp("0.000", "100.000", 0.123));
131 it("computes parameters outside [0, 1]", function () { with (this) {
132 assertEqual("Giving 110%", lerp("Giving 0%", "Giving 100%", 1.1));
135 it("handles multiple numbers", function () { with (this) {
136 var A
= "Chapter 0. The sky was rgb(0, 0, 0).";
137 var B
= "Chapter 10. The sky was rgb(0, 0, 255).";
138 assertEqual(A
, lerp(A
, B
, 0));
139 assertEqual(B
, lerp(A
, B
, 1));
140 assertEqual("Chapter 5. The sky was rgb(0, 0, 128).", lerp(A
, B
, 0.5));
144 JS
.Test
.describe('numeric lerp', function () { with (this) {
145 var lerp
= stringLerp
.numericLerp
;
147 itHandlesBaseCases(this, lerp
);
148 itTreatsNumeralsAsNumbers(this, lerp
);
151 JS
.Test
.describe('auto lerp', function () { with (this) {
152 var lerp
= stringLerp
.lerp
;
154 itHandlesBaseCases(this, lerp
);
155 itMakesValidStrings(this, lerp
);
156 itDoesntOvershoot(this, lerp
);
157 itTreatsNumeralsAsNumbers(this, lerp
);
158 itEditsHumanly(this, lerp
);