Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like EmailContext often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use EmailContext, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 23 | class EmailContext extends BehatContext |
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| 24 | { |
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| 25 | protected $context; |
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| 26 | |||
| 27 | protected $mailer; |
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| 28 | |||
| 29 | /** |
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| 30 | * Stored to simplify later assertions |
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| 31 | */ |
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| 32 | protected $lastMatchedEmail; |
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| 33 | |||
| 34 | /** |
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| 35 | * Initializes context. |
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| 36 | * Every scenario gets it's own context object. |
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| 37 | * |
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| 38 | * @param array $parameters context parameters (set them up through behat.yml) |
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| 39 | */ |
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| 40 | public function __construct(array $parameters) |
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| 45 | |||
| 46 | /** |
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| 47 | * Get Mink session from MinkContext |
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| 48 | */ |
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| 49 | public function getSession($name = null) |
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| 53 | |||
| 54 | /** |
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| 55 | * @BeforeScenario |
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| 56 | */ |
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| 57 | public function before(ScenarioEvent $event) |
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| 65 | |||
| 66 | /** |
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| 67 | * @Given /^there should (not |)be an email (to|from) "([^"]*)"$/ |
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| 68 | */ |
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| 69 | public function thereIsAnEmailFromTo($negate, $direction, $email) |
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| 81 | |||
| 82 | /** |
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| 83 | * @Given /^there should (not |)be an email (to|from) "([^"]*)" titled "([^"]*)"$/ |
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| 84 | */ |
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| 85 | public function thereIsAnEmailFromToTitled($negate, $direction, $email, $subject) |
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| 108 | |||
| 109 | /** |
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| 110 | * Example: Given the email should contain "Thank you for registering!". |
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| 111 | * Assumes an email has been identified by a previous step, |
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| 112 | * e.g. through 'Given there should be an email to "[email protected]"'. |
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| 113 | * |
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| 114 | * @Given /^the email should (not |)contain "([^"]*)"$/ |
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| 115 | */ |
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| 116 | public function thereTheEmailContains($negate, $content) |
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| 136 | |||
| 137 | /** |
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| 138 | * @When /^I click on the "([^"]*)" link in the email (to|from) "([^"]*)"$/ |
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| 139 | */ |
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| 140 | View Code Duplication | public function iGoToInTheEmailTo($linkSelector, $direction, $email) |
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| 155 | |||
| 156 | /** |
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| 157 | * @When /^I click on the "([^"]*)" link in the email (to|from) "([^"]*)" titled "([^"]*)"$/ |
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| 158 | */ |
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| 159 | View Code Duplication | public function iGoToInTheEmailToTitled($linkSelector, $direction, $email, $title) |
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| 173 | |||
| 174 | /** |
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| 175 | * Assumes an email has been identified by a previous step, |
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| 176 | * e.g. through 'Given there should be an email to "[email protected]"'. |
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| 177 | * |
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| 178 | * @When /^I click on the "([^"]*)" link in the email"$/ |
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| 179 | */ |
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| 180 | public function iGoToInTheEmail($linkSelector) |
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| 195 | |||
| 196 | /** |
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| 197 | * @Given /^I clear all emails$/ |
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| 198 | */ |
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| 199 | public function iClearAllEmails() |
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| 204 | |||
| 205 | /** |
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| 206 | * Example: Then the email should contain the following data: |
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| 207 | * | row1 | |
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| 208 | * | row2 | |
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| 209 | * Assumes an email has been identified by a previous step. |
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| 210 | * @Then /^the email should (not |)contain the following data:$/ |
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| 211 | */ |
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| 212 | public function theEmailContainFollowingData($negate, TableNode $table) { |
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| 239 | |||
| 240 | /** |
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| 241 | * @Then /^there should (not |)be an email titled "([^"]*)"$/ |
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| 242 | */ |
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| 243 | public function thereIsAnEmailTitled($negate, $subject) |
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| 257 | |||
| 258 | /** |
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| 259 | * @Then /^the email should (not |)be sent from "([^"]*)"$/ |
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| 260 | */ |
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| 261 | View Code Duplication | public function theEmailSentFrom($negate, $from) |
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| 274 | |||
| 275 | /** |
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| 276 | * @Then /^the email should (not |)be sent to "([^"]*)"$/ |
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| 277 | */ |
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| 278 | View Code Duplication | public function theEmailSentTo($negate, $to) |
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| 291 | } |
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| 292 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: