Add DefaultFractionDigits to Bitcoin CurrencyUnit

Author: msgilligan

digital-currency/bitcoin/src/main/java/org/javamoney/shelter/bitcoin/provider/BitcoinCurrencyProvider.java

@@ -24,14 +24,19 @@
  */
 public final class BitcoinCurrencyProvider implements CurrencyProviderSpi {
 
+    final static int bitcoinFractionDigits = 8;
+
     // Not sure what to do here...
     private final CurrencyContext CONTEXT = CurrencyContextBuilder.of("BitcoinCurrencyContextProvider")
                                                 .build();
 
     private Set<CurrencyUnit> bitcoinSet = new HashSet<>();
 
-    public BitcoinCurrencyProvider(){
-        bitcoinSet.add(CurrencyUnitBuilder.of("BTC", CONTEXT).build());
+    public BitcoinCurrencyProvider() {
+        CurrencyUnit btcUnit = CurrencyUnitBuilder.of("BTC", CONTEXT)
+                                    .setDefaultFractionDigits(bitcoinFractionDigits)
+                                    .build();
+        bitcoinSet.add(btcUnit);
         bitcoinSet = Collections.unmodifiableSet(bitcoinSet);
     }
 

digital-currency/bitcoin/src/test/groovy/org/javamoney/shelter/bitcoin/provider/BitcoinCurrencyProviderSpec.groovy

@@ -39,6 +39,7 @@ class BitcoinCurrencyProviderSpec extends Specification {
         then:
         currencies.size() == 1
         btc.getCurrencyCode() == "BTC"
+        btc.getDefaultFractionDigits() == 8
     }
 
     def "returns Bitcoin for BTC query" () {
@@ -50,6 +51,7 @@ class BitcoinCurrencyProviderSpec extends Specification {
         then:
         currencies.size() == 1
         btc.getCurrencyCode() == "BTC"
+        btc.getDefaultFractionDigits() == 8
     }
 
     def "returns empty for USD query" () {