Fixed default formatters test to reliably work with any system locale

Issue: SPR-13232

spring-context/src/test/java/org/springframework/format/support/FormattingConversionServiceFactoryBeanTests.java

@@ -26,6 +26,7 @@ import java.util.Set;
 
 import org.junit.Test;
 
+import org.springframework.context.i18n.LocaleContextHolder;
 import org.springframework.core.convert.ConversionFailedException;
 import org.springframework.core.convert.TypeDescriptor;
 import org.springframework.format.AnnotationFormatterFactory;
@@ -50,11 +51,18 @@ public class FormattingConversionServiceFactoryBeanTests {
 		factory.afterPropertiesSet();
 		FormattingConversionService fcs = factory.getObject();
 		TypeDescriptor descriptor = new TypeDescriptor(TestBean.class.getDeclaredField("pattern"));
+
+		LocaleContextHolder.setLocale(Locale.GERMAN);
+		try {
 			Object value = fcs.convert("15,00", TypeDescriptor.valueOf(String.class), descriptor);
 			assertEquals(15.0, value);
 			value = fcs.convert(15.0, descriptor, TypeDescriptor.valueOf(String.class));
 			assertEquals("15", value);
 		}
+		finally {
+			LocaleContextHolder.resetLocaleContext();
+		}
+	}
 
 	@Test
 	public void testDefaultFormattersOff() throws Exception {
@@ -63,6 +71,7 @@ public class FormattingConversionServiceFactoryBeanTests {
 		factory.afterPropertiesSet();
 		FormattingConversionService fcs = factory.getObject();
 		TypeDescriptor descriptor = new TypeDescriptor(TestBean.class.getDeclaredField("pattern"));
+
 		try {
 			fcs.convert("15,00", TypeDescriptor.valueOf(String.class), descriptor);
 			fail("This format should not be parseable");