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1 | #!/usr/bin/perl |
2 | |
3 | use strict; |
4 | use warnings; |
5 | |
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6 | use Test::More; |
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7 | |
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8 | { |
9 | package Subject; |
10 | |
11 | use Moose::Role; |
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12 | |
13 | has observers => ( |
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14 | traits => ['Array'], |
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15 | is => 'ro', |
16 | isa => 'ArrayRef[Observer]', |
17 | auto_deref => 1, |
18 | default => sub { [] }, |
19 | handles => { |
20 | 'add_observer' => 'push', |
21 | 'count_observers' => 'count', |
22 | }, |
23 | ); |
24 | |
25 | sub notify { |
26 | my ($self) = @_; |
27 | foreach my $observer ( $self->observers() ) { |
28 | $observer->update($self); |
29 | } |
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30 | } |
31 | } |
32 | |
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33 | { |
34 | package Observer; |
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35 | |
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36 | use Moose::Role; |
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37 | |
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38 | requires 'update'; |
39 | } |
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40 | |
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41 | { |
42 | package Counter; |
43 | |
44 | use Moose; |
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45 | |
46 | with 'Subject'; |
47 | |
48 | has count => ( |
49 | traits => ['Counter'], |
50 | is => 'ro', |
51 | isa => 'Int', |
52 | default => 0, |
53 | handles => { |
54 | inc_counter => 'inc', |
55 | dec_counter => 'dec', |
56 | }, |
57 | ); |
58 | |
59 | after qw(inc_counter dec_counter) => sub { |
60 | my ($self) = @_; |
61 | $self->notify(); |
62 | }; |
63 | } |
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64 | |
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65 | { |
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66 | |
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67 | package Display; |
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68 | |
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69 | use Test::More; |
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70 | |
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71 | use Moose; |
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72 | |
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73 | with 'Observer'; |
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74 | |
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75 | sub update { |
76 | my ( $self, $subject ) = @_; |
77 | like $subject->count, qr{^-?\d+$}, |
78 | 'Observed number ' . $subject->count; |
79 | } |
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80 | } |
81 | |
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82 | package main; |
83 | |
84 | my $count = Counter->new(); |
85 | |
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86 | ok( $count->can('add_observer'), 'add_observer method added' ); |
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87 | |
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88 | ok( $count->can('count_observers'), 'count_observers method added' ); |
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89 | |
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90 | ok( $count->can('inc_counter'), 'inc_counter method added' ); |
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91 | |
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92 | ok( $count->can('dec_counter'), 'dec_counter method added' ); |
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93 | |
94 | $count->add_observer( Display->new() ); |
95 | |
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96 | is( $count->count_observers, 1, 'Only one observer' ); |
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97 | |
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98 | is( $count->count, 0, 'Default to zero' ); |
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99 | |
100 | $count->inc_counter; |
101 | |
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102 | is( $count->count, 1, 'Increment to one ' ); |
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103 | |
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104 | $count->inc_counter for ( 1 .. 6 ); |
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105 | |
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106 | is( $count->count, 7, 'Increment up to seven' ); |
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107 | |
108 | $count->dec_counter; |
109 | |
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110 | is( $count->count, 6, 'Decrement to 6' ); |
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111 | |
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112 | $count->dec_counter for ( 1 .. 5 ); |
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113 | |
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114 | is( $count->count, 1, 'Decrement to 1' ); |
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115 | |
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116 | $count->dec_counter for ( 1 .. 2 ); |
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117 | |
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118 | is( $count->count, -1, 'Negative numbers' ); |
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119 | |
120 | $count->inc_counter; |
121 | |
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122 | is( $count->count, 0, 'Back to zero' ); |
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123 | |
124 | done_testing; |