prosody
d54a0e129af8
spec/util_promise_spec.lua

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spec/util_promise_spec.lua @ 9456:d54a0e129af8

util.promise: ES6-like API for promises
author Matthew Wild <mwild1@gmail.com>
date Wed, 10 Oct 2018 17:45:19 +0100
child 9457:d01cff2f7a26
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9455:c62c983b8be3 9456:d54a0e129af8
1 local promise = require "util.promise";
2
3 describe("util.promise", function ()
4 describe("new()", function ()
5 it("returns a promise object", function ()
6 assert(promise.new());
7 end);
8 end);
9 it("notifies immediately for fulfilled promises", function ()
10 local p = promise.new(function (resolve)
11 resolve("foo");
12 end);
13 local cb = spy.new(function (v)
14 assert.equal("foo", v);
15 end);
16 p:next(cb);
17 assert.spy(cb).was_called(1);
18 end);
19 it("notifies on fulfilment of pending promises", function ()
20 local r;
21 local p = promise.new(function (resolve)
22 r = resolve;
23 end);
24 local cb = spy.new(function (v)
25 assert.equal("foo", v);
26 end);
27 p:next(cb);
28 assert.spy(cb).was_called(0);
29 r("foo");
30 assert.spy(cb).was_called(1);
31 end);
32 it("allows chaining :next() calls", function ()
33 local r;
34 local result;
35 local p = promise.new(function (resolve)
36 r = resolve;
37 end);
38 local cb1 = spy.new(function (v)
39 assert.equal("foo", v);
40 return "bar";
41 end);
42 local cb2 = spy.new(function (v)
43 assert.equal("bar", v);
44 result = v;
45 end);
46 p:next(cb1):next(cb2);
47 assert.spy(cb1).was_called(0);
48 assert.spy(cb2).was_called(0);
49 r("foo");
50 assert.spy(cb1).was_called(1);
51 assert.spy(cb2).was_called(1);
52 assert.equal("bar", result);
53 end);
54 it("supports multiple :next() calls on the same promise", function ()
55 local r;
56 local result;
57 local p = promise.new(function (resolve)
58 r = resolve;
59 end);
60 local cb1 = spy.new(function (v)
61 assert.equal("foo", v);
62 result = v;
63 end);
64 local cb2 = spy.new(function (v)
65 assert.equal("foo", v);
66 result = v;
67 end);
68 p:next(cb1);
69 p:next(cb2);
70 assert.spy(cb1).was_called(0);
71 assert.spy(cb2).was_called(0);
72 r("foo");
73 assert.spy(cb1).was_called(1);
74 assert.spy(cb2).was_called(1);
75 assert.equal("foo", result);
76 end);
77 it("automatically rejects on error", function ()
78 local r;
79 local p = promise.new(function (resolve)
80 r = resolve;
81 error("oh no");
82 end);
83 local cb = spy.new(function () end);
84 local err_cb = spy.new(function (v)
85 assert.equal("oh no", v);
86 end);
87 p:next(cb, err_cb);
88 assert.spy(cb).was_called(0);
89 assert.spy(err_cb).was_called(1);
90 r("foo");
91 assert.spy(cb).was_called(0);
92 assert.spy(err_cb).was_called(1);
93 end);
94 it("supports reject()", function ()
95 local r, result;
96 local p = promise.new(function (resolve, reject)
97 r = reject;
98 end);
99 local cb = spy.new(function () end);
100 local err_cb = spy.new(function (v)
101 result = v;
102 assert.equal("oh doh", v);
103 end);
104 p:next(cb, err_cb);
105 assert.spy(cb).was_called(0);
106 assert.spy(err_cb).was_called(0);
107 r("oh doh");
108 assert.spy(cb).was_called(0);
109 assert.spy(err_cb).was_called(1);
110 assert.equal("oh doh", result);
111 end);
112 it("supports chaining of rejected promises", function ()
113 local r, result;
114 local p = promise.new(function (resolve, reject)
115 r = reject;
116 end);
117 local cb = spy.new(function () end);
118 local err_cb = spy.new(function (v)
119 result = v;
120 assert.equal("oh doh", v);
121 return "ok"
122 end);
123 local cb2 = spy.new(function (v)
124 result = v;
125 end);
126 local err_cb2 = spy.new(function (v) end);
127 p:next(cb, err_cb):next(cb2, err_cb2)
128 assert.spy(cb).was_called(0);
129 assert.spy(err_cb).was_called(0);
130 assert.spy(cb2).was_called(0);
131 assert.spy(err_cb2).was_called(0);
132 r("oh doh");
133 assert.spy(cb).was_called(0);
134 assert.spy(err_cb).was_called(1);
135 assert.spy(cb2).was_called(1);
136 assert.spy(err_cb2).was_called(0);
137 assert.equal("ok", result);
138 end);
139
140 describe("race()", function ()
141 it("works with fulfilled promises", function ()
142 local p1, p2 = promise.resolve("yep"), promise.resolve("nope");
143 local p = promise.race({ p1, p2 });
144 local result;
145 p:next(function (v)
146 result = v;
147 end);
148 assert.equal("yep", result);
149 end);
150 it("works with pending promises", function ()
151 local r1, r2;
152 local p1, p2 = promise.new(function (resolve) r1 = resolve end), promise.new(function (resolve) r2 = resolve end);
153 local p = promise.race({ p1, p2 });
154
155 local result;
156 local cb = spy.new(function (v)
157 result = v;
158 end);
159 p:next(cb);
160 assert.spy(cb).was_called(0);
161 r2("yep");
162 r1("nope");
163 assert.spy(cb).was_called(1);
164 assert.equal("yep", result);
165 end);
166 end);
167 describe("all()", function ()
168 it("works with fulfilled promises", function ()
169 local p1, p2 = promise.resolve("yep"), promise.resolve("nope");
170 local p = promise.all({ p1, p2 });
171 local result;
172 p:next(function (v)
173 result = v;
174 end);
175 assert.same({ "yep", "nope" }, result);
176 end);
177 it("works with pending promises", function ()
178 local r1, r2;
179 local p1, p2 = promise.new(function (resolve) r1 = resolve end), promise.new(function (resolve) r2 = resolve end);
180 local p = promise.all({ p1, p2 });
181
182 local result;
183 local cb = spy.new(function (v)
184 result = v;
185 end);
186 p:next(cb);
187 assert.spy(cb).was_called(0);
188 r2("yep");
189 assert.spy(cb).was_called(0);
190 r1("nope");
191 assert.spy(cb).was_called(1);
192 assert.same({ "nope", "yep" }, result);
193 end);
194 it("rejects if any promise rejects", function ()
195 local r1, r2;
196 local p1 = promise.new(function (resolve, reject) r1 = reject end);
197 local p2 = promise.new(function (resolve, reject) r2 = reject end);
198 local p = promise.all({ p1, p2 });
199
200 local result;
201 local cb = spy.new(function (v)
202 result = v;
203 end);
204 local cb_err = spy.new(function (v)
205 result = v;
206 end);
207 p:next(cb, cb_err);
208 assert.spy(cb).was_called(0);
209 assert.spy(cb_err).was_called(0);
210 r2("fail");
211 assert.spy(cb).was_called(0);
212 assert.spy(cb_err).was_called(1);
213 r1("nope");
214 assert.spy(cb).was_called(0);
215 assert.spy(cb_err).was_called(1);
216 assert.equal("fail", result);
217 end);
218 end);
219 describe("catch()", function ()
220 it("works", function ()
221 local result;
222 local p = promise.new(function (resolve)
223 error({ foo = true });
224 end);
225 local cb1 = spy.new(function (v)
226 result = v;
227 end);
228 assert.spy(cb1).was_called(0);
229 p:catch(cb1);
230 assert.spy(cb1).was_called(1);
231 assert.same({ foo = true }, result);
232 end);
233 end);
234 it("promises may be resolved by other promises", function ()
235 local r1, r2;
236 local p1, p2 = promise.new(function (resolve) r1 = resolve end), promise.new(function (resolve) r2 = resolve end);
237
238 local result;
239 local cb = spy.new(function (v)
240 result = v;
241 end);
242 p1:next(cb);
243 assert.spy(cb).was_called(0);
244
245 r1(p2);
246 assert.spy(cb).was_called(0);
247 r2("yep");
248 assert.spy(cb).was_called(1);
249 assert.equal("yep", result);
250 end);
251 describe("reject()", function ()
252 it("returns a rejected promise", function ()
253 local p = promise.reject("foo");
254 local cb = spy.new(function (v)
255 result = v;
256 end);
257 p:next(cb);
258 assert.spy(cb).was_called(1);
259 assert.spy(cb).was_called_with("foo");
260 end);
261 end);
262 end);