Drop CurrencyProvider interface

Multiple implementations made sense only when methods accepting a currency code provided support for non-ISO currencies.
This support has been dropped as it required a global configuration for currency providers.
ISOCurrencyProvider is now the only provider available, hence moved to the base namespace.

src/Currency.php

@@ -2,7 +2,7 @@
 
 namespace Brick\Money;
 
-use Brick\Money\CurrencyProvider\ISOCurrencyProvider;
+use Brick\Money\ISOCurrencyProvider;
 use Brick\Money\Exception\UnknownCurrencyException;
 
 /**

src/CurrencyProvider/ISOCurrencyProvider.php → src/ISOCurrencyProvider.php

@@ -1,15 +1,13 @@
 <?php
 
-namespace Brick\Money\CurrencyProvider;
+namespace Brick\Money;
 
-use Brick\Money\Currency;
-use Brick\Money\CurrencyProvider;
 use Brick\Money\Exception\UnknownCurrencyException;
 
 /**
- * Built-in provider for ISO currencies.
+ * Provides ISO 4217 currencies.
  */
-class ISOCurrencyProvider implements CurrencyProvider
+class ISOCurrencyProvider
 {
     /**
      * @var ISOCurrencyProvider|null
@@ -53,7 +51,7 @@ class ISOCurrencyProvider implements CurrencyProvider
      */
     private function __construct()
     {
-        $this->currencyData = require __DIR__ . '/../../data/iso-currencies.php';
+        $this->currencyData = require __DIR__ . '/../data/iso-currencies.php';
     }
 
     /**
@@ -71,7 +69,13 @@ public static function getInstance()
     }
 
     /**
-     * {@inheritdoc}
+     * Returns the currency matching the given currency code.
+     *
+     * @param string $currencyCode The ISO 4217 currency code.
+     *
+     * @return Currency The currency.
+     *
+     * @throws UnknownCurrencyException If the currency code is not known.
      */
     public function getCurrency($currencyCode)
     {
@@ -89,7 +93,9 @@ public function getCurrency($currencyCode)
     }
 
     /**
-     * {@inheritdoc}
+     * Returns all the available currencies.
+     *
+     * @return Currency[] The currencies, indexed by currency code.
      */
     public function getAvailableCurrencies()
     {
@@ -100,6 +106,8 @@ public function getAvailableCurrencies()
                 }
             }
 
+            ksort($this->currencies);
+
             $this->isPartial = false;
         }
 
@@ -150,7 +158,7 @@ public function getCurrencyForCountry($countryCode)
     public function getCurrenciesForCountry($countryCode)
     {
         if ($this->countryToCurrency === null) {
-            $this->countryToCurrency = require __DIR__ . '/../../data/country-to-currency.php';
+            $this->countryToCurrency = require __DIR__ . '/../data/country-to-currency.php';
         }
 
         $result = [];

tests/AbstractTestCase.php

@@ -4,7 +4,6 @@
 
 use Brick\Money\Context;
 use Brick\Money\Currency;
-use Brick\Money\CurrencyProvider;
 use Brick\Money\Money;
 use Brick\Money\MoneyBag;
 use Brick\Money\RationalMoney;

tests/CurrencyProvider/ISOCurrencyProviderTest.php

@@ -3,7 +3,7 @@
 namespace Brick\Money\Tests\CurrencyProvider;
 
 use Brick\Money\Currency;
-use Brick\Money\CurrencyProvider\ISOCurrencyProvider;
+use Brick\Money\ISOCurrencyProvider;
 use Brick\Money\Tests\AbstractTestCase;
 
 /**