Solves #34, adds 100% code coverage for CurrencyPair

lib/Money/CurrencyPair.php

@@ -14,21 +14,21 @@ namespace Money;
 class CurrencyPair
 {
     /** @var Currency */
-    private $counterCurrency;
+    private $baseCurrency;
 
     /** @var Currency */
-    private $baseCurrency;
+    private $counterCurrency;
 
     /** @var float */
     private $ratio;
 
     /**
-     * @param \Money\Currency $counterCurrency
      * @param \Money\Currency $baseCurrency
+     * @param \Money\Currency $counterCurrency
      * @param float $ratio
      * @throws \Money\InvalidArgumentException
      */
-    public function __construct(Currency $counterCurrency, Currency $baseCurrency, $ratio)
+    public function __construct(Currency $baseCurrency, Currency $counterCurrency, $ratio)
     {
         if(!is_numeric($ratio)) {
             throw new InvalidArgumentException("Ratio must be numeric");
@@ -70,12 +70,12 @@ class CurrencyPair
      */
     public function convert(Money $money)
     {
-        if (!$money->getCurrency()->equals($this->counterCurrency)) {
+        if (!$money->getCurrency()->equals($this->baseCurrency)) {
             throw new InvalidArgumentException("The Money has the wrong currency");
         }
 
         // @todo add rounding mode?
-        return new Money((int) round($money->getAmount() * $this->ratio), $this->baseCurrency);
+        return new Money((int) round($money->getAmount() * $this->ratio), $this->counterCurrency);
     }
 
     /** @return \Money\Currency */

tests/Money/Tests/CurrencyPairTest.php

@@ -48,4 +48,68 @@ class CurrencyPairTest extends PHPUnit_Framework_TestCase
     {
         CurrencyPair::createFromIso('1.2500');
     }
+
+    /**
+     * @test
+     * @expectedException \Money\InvalidArgumentException
+     * @expectedExceptionMessage Ratio must be numeric
+     * @dataProvider dataProviderNonNumericRatio
+     */
+    public function testConstructorWithNonNumericRatio($nonNumericRatio)
+    {
+        new CurrencyPair(new Currency('EUR'), new Currency('USD'), $nonNumericRatio);
+    }
+
+    /**
+     * @test
+     */
+    public function testGetRatio()
+    {
+        $ratio = 1.2500;
+        $pair  = new CurrencyPair(new Currency('EUR'), new Currency('USD'), $ratio);
+
+        $this->assertEquals($ratio, $pair->getRatio());
+    }
+
+    /**
+     * @test
+     */
+    public function testGetBaseCurrency()
+    {
+        $pair = new CurrencyPair(new Currency('EUR'), new Currency('USD'), 1.2500);
+
+        $this->assertEquals(new Currency('EUR'), $pair->getBaseCurrency());
+    }
+
+    /**
+     * @test
+     */
+    public function testGetCounterCurrency()
+    {
+        $pair = new CurrencyPair(new Currency('EUR'), new Currency('USD'), 1.2500);
+
+        $this->assertEquals(new Currency('USD'), $pair->getCounterCurrency());
+    }
+
+    /**
+     * @test
+     * @expectedException \Money\InvalidArgumentException
+     * @expectedExceptionMessage The Money has the wrong currency
+     */
+    public function testConvertWithInvalidCurrency()
+    {
+        $money = new Money(100, new Currency('JPY'));
+        $pair = new CurrencyPair(new Currency('EUR'), new Currency('USD'), 1.2500);
+
+        $pair->convert($money);
+    }
+
+    public function dataProviderNonNumericRatio()
+    {
+        return array(
+            array('NonNumericRatio'),
+            array('16AlsoIncorrect'),
+            array('10.00ThisIsToo')
+        );
+    }
 }