1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
|
require_relative '../../spec_helper'
require_relative 'fixtures/classes'
describe "Module#prepend" do
it "is a public method" do
Module.should have_public_instance_method(:prepend, false)
end
it "does not affect the superclass" do
Class.new { prepend Module.new }.superclass.should == Object
end
it "calls #prepend_features(self) in reversed order on each module" do
ScratchPad.record []
m = Module.new do
def self.prepend_features(mod)
ScratchPad << [ self, mod ]
end
end
m2 = Module.new do
def self.prepend_features(mod)
ScratchPad << [ self, mod ]
end
end
m3 = Module.new do
def self.prepend_features(mod)
ScratchPad << [ self, mod ]
end
end
c = Class.new { prepend(m, m2, m3) }
ScratchPad.recorded.should == [ [ m3, c], [ m2, c ], [ m, c ] ]
end
it "raises a TypeError when the argument is not a Module" do
lambda { ModuleSpecs::Basic.prepend(Class.new) }.should raise_error(TypeError)
end
it "does not raise a TypeError when the argument is an instance of a subclass of Module" do
lambda { ModuleSpecs::SubclassSpec.prepend(ModuleSpecs::Subclass.new) }.should_not raise_error(TypeError)
end
it "imports constants" do
m1 = Module.new
m1::MY_CONSTANT = 1
m2 = Module.new { prepend(m1) }
m2.constants.should include(:MY_CONSTANT)
end
it "imports instance methods" do
Module.new { prepend ModuleSpecs::A }.instance_methods.should include(:ma)
end
it "does not import methods to modules and classes" do
Module.new { prepend ModuleSpecs::A }.methods.should_not include(:ma)
end
it "allows wrapping methods" do
m = Module.new { def calc(x) super + 3 end }
c = Class.new { def calc(x) x*2 end }
c.prepend(m)
c.new.calc(1).should == 5
end
it "also prepends included modules" do
a = Module.new { def calc(x) x end }
b = Module.new { include a }
c = Class.new { prepend b }
c.new.calc(1).should == 1
end
it "prepends multiple modules in the right order" do
m1 = Module.new { def chain; super << :m1; end }
m2 = Module.new { def chain; super << :m2; end; prepend(m1) }
c = Class.new { def chain; [:c]; end; prepend(m2) }
c.new.chain.should == [:c, :m2, :m1]
end
it "includes prepended modules in ancestors" do
m = Module.new
Class.new { prepend(m) }.ancestors.should include(m)
end
it "reports the prepended module as the method owner" do
m = Module.new { def meth; end }
c = Class.new { def meth; end; prepend(m) }
c.new.method(:meth).owner.should == m
end
it "reports the prepended module as the unbound method owner" do
m = Module.new { def meth; end }
c = Class.new { def meth; end; prepend(m) }
c.instance_method(:meth).owner.should == m
c.public_instance_method(:meth).owner.should == m
end
it "causes the prepended module's method to be aliased by alias_method" do
m = Module.new { def meth; :m end }
c = Class.new { def meth; :c end; prepend(m); alias_method :alias, :meth }
c.new.alias.should == :m
end
it "reports the class for the owner of an aliased method on the class" do
m = Module.new
c = Class.new { prepend(m); def meth; :c end; alias_method :alias, :meth }
c.instance_method(:alias).owner.should == c
end
it "reports the class for the owner of a method aliased from the prepended module" do
m = Module.new { def meth; :m end }
c = Class.new { prepend(m); alias_method :alias, :meth }
c.instance_method(:alias).owner.should == c
end
it "sees an instance of a prepended class as kind of the prepended module" do
m = Module.new
c = Class.new { prepend(m) }
c.new.should be_kind_of(m)
end
it "keeps the module in the chain when dupping the class" do
m = Module.new
c = Class.new { prepend(m) }
c.dup.new.should be_kind_of(m)
end
it "keeps the module in the chain when dupping an intermediate module" do
m1 = Module.new { def calc(x) x end }
m2 = Module.new { prepend(m1) }
c1 = Class.new { prepend(m2) }
m2dup = m2.dup
m2dup.ancestors.should == [m2dup,m1,m2]
c2 = Class.new { prepend(m2dup) }
c1.ancestors[0,3].should == [m1,m2,c1]
c1.new.should be_kind_of(m1)
c2.ancestors[0,4].should == [m2dup,m1,m2,c2]
c2.new.should be_kind_of(m1)
end
it "depends on prepend_features to add the module" do
m = Module.new { def self.prepend_features(mod) end }
Class.new { prepend(m) }.ancestors.should_not include(m)
end
it "adds the module in the subclass chains" do
parent = Class.new { def chain; [:parent]; end }
child = Class.new(parent) { def chain; super << :child; end }
mod = Module.new { def chain; super << :mod; end }
parent.prepend(mod)
parent.ancestors[0,2].should == [mod, parent]
child.ancestors[0,3].should == [child, mod, parent]
parent.new.chain.should == [:parent, :mod]
child.new.chain.should == [:parent, :mod, :child]
end
it "inserts a later prepended module into the chain" do
m1 = Module.new { def chain; super << :m1; end }
m2 = Module.new { def chain; super << :m2; end }
c1 = Class.new { def chain; [:c1]; end; prepend m1 }
c2 = Class.new(c1) { def chain; super << :c2; end }
c2.new.chain.should == [:c1, :m1, :c2]
c1.prepend(m2)
c2.new.chain.should == [:c1, :m1, :m2, :c2]
end
it "works with subclasses" do
m = Module.new do
def chain
super << :module
end
end
c = Class.new do
prepend m
def chain
[:class]
end
end
s = Class.new(c) do
def chain
super << :subclass
end
end
s.new.chain.should == [:class, :module, :subclass]
end
it "throws a NoMethodError when there is no more superclass" do
m = Module.new do
def chain
super << :module
end
end
c = Class.new do
prepend m
def chain
super << :class
end
end
lambda { c.new.chain }.should raise_error(NoMethodError)
end
it "calls prepended after prepend_features" do
ScratchPad.record []
m = Module.new do
def self.prepend_features(klass)
ScratchPad << [:prepend_features, klass]
end
def self.prepended(klass)
ScratchPad << [:prepended, klass]
end
end
c = Class.new { prepend(m) }
ScratchPad.recorded.should == [[:prepend_features, c], [:prepended, c]]
end
it "detects cyclic prepends" do
lambda {
module ModuleSpecs::P
prepend ModuleSpecs::P
end
}.should raise_error(ArgumentError)
end
it "doesn't accept no-arguments" do
lambda {
Module.new do
prepend
end
}.should raise_error(ArgumentError)
end
it "returns the class it's included into" do
m = Module.new
r = nil
c = Class.new { r = prepend m }
r.should == c
end
it "clears any caches" do
module ModuleSpecs::M3
module PM1
def foo
:m1
end
end
module PM2
def foo
:m2
end
end
klass = Class.new do
prepend PM1
def get
foo
end
end
o = klass.new
o.get.should == :m1
klass.class_eval do
prepend PM2
end
o.get.should == :m2
end
end
it "supports super when the module is prepended into a singleton class" do
ScratchPad.record []
mod = Module.new do
def self.inherited(base)
super
end
end
module_with_singleton_class_prepend = Module.new do
singleton_class.prepend(mod)
end
klass = Class.new(ModuleSpecs::RecordIncludedModules) do
include module_with_singleton_class_prepend
end
ScratchPad.recorded.should == klass
end
it "supports super when the module is prepended into a singleton class with a class super" do
ScratchPad.record []
base_class = Class.new(ModuleSpecs::RecordIncludedModules) do
def self.inherited(base)
super
end
end
prepended_module = Module.new
base_class.singleton_class.prepend(prepended_module)
child_class = Class.new(base_class)
ScratchPad.recorded.should == child_class
end
it "does not interfere with a define_method super in the original class" do
base_class = Class.new do
def foo(ary)
ary << 1
end
end
child_class = Class.new(base_class) do
define_method :foo do |ary|
ary << 2
super(ary)
end
end
prep_mod = Module.new do
def foo(ary)
ary << 3
super(ary)
end
end
child_class.prepend(prep_mod)
ary = []
child_class.new.foo(ary)
ary.should == [3, 2, 1]
end
describe "called on a module" do
describe "included into a class"
it "does not obscure the module's methods from reflective access" do
mod = Module.new do
def foo; end
end
cls = Class.new do
include mod
end
pre = Module.new
mod.prepend pre
cls.instance_methods.should include(:foo)
end
end
end
|