Practical Test-driven Development Presentation

Code That Accesses Databases

•Some options

•Run the tests in a virtual machine

•Mock the database interaction layer

•Use a lightweight database such as SQLite

191

Mocking the Database Access Layer

Case Studies

“t/test_with_dbi_mock.t”

1 use warnings;

2 use strict;

3 use Test::More qw(no_plan);

4

5 BEGIN { use_ok( 'PrimeNumberIterator' ) };

192

Mocking the Database Access Layer

Case Studies

--(0)> prove -Ilib t/test_with_dbi_mock.t

t/test_with_dbi_mock....

#Failed test 'use PrimeNumberIterator;'

#at t/test_with_dbi_mock.t line 5.

#Tried to use 'PrimeNumberIterator'.

#Error: Can't locate PrimeNumberIterator.pm in @INC (@INC contains: ....) at (eval 3) line 2.

# BEGIN failed--compilation aborted at t/test_with_dbi_mock.t line 5.

# Looks like you failed	1 test of 1.
t/test_with_dbi_mock....	dubious
Test returned status 1 (wstat 256, 0x100)
DIED. FAILED test 1
Failed 1/1 tests, 0.00% okay
Failed Test	Stat Wstat Total Fail List of Failed

-------------------------------------------------------------------------------

t/test_with_dbi_mock.t		1 256	1	1 1
Failed	1/1 test scripts. 1/1 subtests		failed.
Files=1, Tests=1, 0 wallclock secs (			0.02	cusr + 0.01 csys = 0.03 CPU)
Failed	1/1 test programs. 1/1 subtests failed.

193

Mocking the Database Access Layer

Case Studies

“lib/PrimeNumberIterator.pm”

1 package PrimeNumberIterator;

2

3 use warnings;

4 use strict;

5

6 1;

194

Mocking the Database Access Layer

Case Studies

--(0)> prove -Ilib t/test_with_dbi_mock.t t/test_with_dbi_mock....ok

All tests successful.

Files=1, Tests=1, 1 wallclock secs ( 0.02 cusr + 0.01 csys = 0.03 CPU)

195

Mocking the Database Access Layer

Case Studies

“t/test_with_dbi_mock.t”

1 use warnings;

2 use strict;

3 use Test::More qw(no_plan);

4

5 BEGIN { use_ok( 'PrimeNumberIterator' ) };

6

7 can_ok( 'PrimeNumberIterator', qw(new) );

196

Mocking the Database Access Layer

Case Studies

--(0)> prove -Ilib t/test_with_dbi_mock.t

t/test_with_dbi_mock....

#Failed test 'PrimeNumberIterator->can('new')'

#at t/test_with_dbi_mock.t line 7.

#PrimeNumberIterator->can('new') failed

#Looks like you failed 1 test of 2.

t/test_with_dbi_mock	....dubious
Test returned status 1 (wstat 256, 0x100)
DIED. FAILED test 2
Failed 1/2 tests, 50.00% okay
Failed Test	Stat Wstat Total Fail List of Failed

-------------------------------------------------------------------------------

t/test_with_dbi_mock.t		1 256	2	1 2
Failed	1/1 test scripts. 1/2 subtests		failed.
Files=1, Tests=2, 0 wallclock secs (			0.02	cusr + 0.01 csys = 0.03 CPU)
Failed	1/1 test programs. 1/2 subtests failed.

197

Mocking the Database Access Layer

Case Studies

“lib/PrimeNumberIterator.pm”

1 package PrimeNumberIterator;

2

3 use warnings;

4 use strict;

5

6 sub new {}

7

8 1;

198

Mocking the Database Access Layer

Case Studies

--(0)> prove -Ilib t/test_with_dbi_mock.t t/test_with_dbi_mock....ok

All tests successful.

Files=1, Tests=2, 1 wallclock secs ( 0.02 cusr + 0.01 csys = 0.03 CPU)

199

Mocking the Database Access Layer

Case Studies

“t/test_with_dbi_mock.t”

5 BEGIN { use_ok( 'PrimeNumberIterator' ) };

6

7 can_ok( 'PrimeNumberIterator', qw(new) );

8

9 my $p = PrimeNumberIterator->new();

10 isa_ok( $p, 'PrimeNumberIterator' );

200