Code review.

Author: Ekman

.travis.yml

@@ -4,4 +4,4 @@ php:
   - '7.1'
   - '7.2'
 before_script: composer install
-script: vendor/bin/phpunit
+script: vendor/bin/phpunit

README.md

@@ -1,4 +1,6 @@
-# Luhn Algorithm in PHP
+# Luhn Algorithm
+
+[![Build Status](https://travis-ci.org/Ekman/Luhn-Algorithm.svg?branch=master)](https://travis-ci.org/Ekman/Luhn-Algorithm)
 
 This is an implementation of the Luhn Algorithm in PHP. The Luhn Algorithm is
 used to validate things like credit cards and national identifcation numbers.
@@ -26,5 +28,5 @@ if ($luhn->isValid(123456789)) {
 
 $checkSum = $luhn->calcCheckSum(123456789);
 
-$checkDigit = $luhn->calcCheckDigit();
+$checkDigit = $luhn->calcCheckDigit(123456789);
 ```

src/LuhnAlgorithm.php

@@ -90,4 +90,4 @@ public function calcChecksum(int $input): int {
 
 		return $checkSum;
 	}
-}
+}

tests/LuhnAlgorithmTest.php

@@ -81,4 +81,4 @@ public function provideCalcCheckDigit_success() {
 			[410321920, 2],
 		];
 	}
-}
+}