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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| 22 | class EmailContext extends BehatContext |
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| 23 | { |
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| 24 | protected $context; |
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| 25 | |||
| 26 | protected $mailer; |
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| 27 | |||
| 28 | /** |
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| 29 | * Stored to simplify later assertions |
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| 30 | */ |
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| 31 | protected $lastMatchedEmail; |
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| 32 | |||
| 33 | /** |
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| 34 | * Initializes context. |
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| 35 | * Every scenario gets it's own context object. |
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| 36 | * |
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| 37 | * @param array $parameters context parameters (set them up through behat.yml) |
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| 38 | */ |
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| 39 | public function __construct(array $parameters) |
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| 44 | |||
| 45 | /** |
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| 46 | * Get Mink session from MinkContext |
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| 47 | */ |
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| 48 | public function getSession($name = null) |
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| 52 | |||
| 53 | /** |
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| 54 | * @BeforeScenario |
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| 55 | */ |
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| 56 | public function before(ScenarioEvent $event) |
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| 64 | |||
| 65 | /** |
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| 66 | * @Given /^there should (not |)be an email (to|from) "([^"]*)"$/ |
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| 67 | */ |
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| 68 | public function thereIsAnEmailFromTo($negate, $direction, $email) |
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| 80 | |||
| 81 | /** |
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| 82 | * @Given /^there should (not |)be an email (to|from) "([^"]*)" titled "([^"]*)"$/ |
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| 83 | */ |
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| 84 | public function thereIsAnEmailFromToTitled($negate, $direction, $email, $subject) |
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| 109 | |||
| 110 | /** |
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| 111 | * Example: Given the email should contain "Thank you for registering!". |
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| 112 | * Assumes an email has been identified by a previous step, |
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| 113 | * e.g. through 'Given there should be an email to "[email protected]"'. |
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| 114 | * |
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| 115 | * @Given /^the email should (not |)contain "([^"]*)"$/ |
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| 116 | */ |
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| 117 | public function thereTheEmailContains($negate, $content) |
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| 137 | |||
| 138 | /** |
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| 139 | * Example: Given the email contains "Thank you for <strong>registering!<strong>". |
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| 140 | * Then the email should contain plain text "Thank you for registering!" |
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| 141 | * Assumes an email has been identified by a previous step, |
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| 142 | * e.g. through 'Given there should be an email to "[email protected]"'. |
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| 143 | * |
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| 144 | * @Given /^the email should contain plain text "([^"]*)"$/ |
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| 145 | */ |
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| 146 | public function thereTheEmailContainsPlainText($content) |
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| 159 | |||
| 160 | /** |
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| 161 | * @When /^I click on the "([^"]*)" link in the email (to|from) "([^"]*)"$/ |
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| 162 | */ |
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| 163 | View Code Duplication | public function iGoToInTheEmailTo($linkSelector, $direction, $email) |
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| 178 | |||
| 179 | /** |
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| 180 | * @When /^I click on the "([^"]*)" link in the email (to|from) "([^"]*)" titled "([^"]*)"$/ |
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| 181 | */ |
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| 182 | View Code Duplication | public function iGoToInTheEmailToTitled($linkSelector, $direction, $email, $title) |
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| 196 | |||
| 197 | /** |
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| 198 | * Assumes an email has been identified by a previous step, |
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| 199 | * e.g. through 'Given there should be an email to "[email protected]"'. |
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| 200 | * |
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| 201 | * @When /^I click on the "([^"]*)" link in the email"$/ |
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| 202 | */ |
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| 203 | public function iGoToInTheEmail($linkSelector) |
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| 218 | |||
| 219 | /** |
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| 220 | * @Given /^I clear all emails$/ |
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| 221 | */ |
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| 222 | public function iClearAllEmails() |
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| 227 | |||
| 228 | /** |
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| 229 | * Example: Then the email should contain the following data: |
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| 230 | * | row1 | |
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| 231 | * | row2 | |
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| 232 | * Assumes an email has been identified by a previous step. |
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| 233 | * @Then /^the email should (not |)contain the following data:$/ |
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| 234 | */ |
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| 235 | public function theEmailContainFollowingData($negate, TableNode $table) |
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| 264 | |||
| 265 | /** |
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| 266 | * @Then /^there should (not |)be an email titled "([^"]*)"$/ |
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| 267 | */ |
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| 268 | public function thereIsAnEmailTitled($negate, $subject) |
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| 282 | |||
| 283 | /** |
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| 284 | * @Then /^the email should (not |)be sent from "([^"]*)"$/ |
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| 285 | */ |
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| 286 | View Code Duplication | public function theEmailSentFrom($negate, $from) |
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| 299 | |||
| 300 | /** |
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| 301 | * @Then /^the email should (not |)be sent to "([^"]*)"$/ |
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| 302 | */ |
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| 303 | View Code Duplication | public function theEmailSentTo($negate, $to) |
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| 316 | } |
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| 317 |
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: