use different implementation

by @pkriens
adjust testcases since this version uses different messages and treats MERGE differently than the previous implementation.
Basically now if a MERGE is not supported / possible, then the existing file is kept (is NOT overwritten).

Signed-off-by: Christoph Rueger <chrisrueger@gmail.com>

biz.aQute.bndlib.tests/test/test/IncludeResourceTest.java

@@ -195,7 +195,7 @@ public void testIncludeResourceDuplicatesDefaultOverwrite() throws Exception {
 			Jar jar = a.build();
 			assertFalse(a.check());
 			assertEquals(
-				"Duplicate file overwritten: META-INF/services/foo (Consider using the onduplicate: directive to handle duplicates.)",
+				"includeresource.duplicates: Duplicate overwritten: META-INF/services/foo (Consider using the onduplicate: directive to handle duplicates.)",
 				a.getWarnings()
 					.get(0));
 
@@ -266,7 +266,7 @@ public void testIncludeResourceMixedMetaInfDuplicatesMerge() throws Exception {
 			assertEquals("a\nb", IO.collect(resourceFoo.openInputStream()));
 
 			Resource resourceManifest = jar.getResource("META-INF/bar.txt");
-			assertEquals("b", IO.collect(resourceManifest.openInputStream()));
+			assertEquals("a", IO.collect(resourceManifest.openInputStream()));
 
 		}
 	}
@@ -300,7 +300,7 @@ public void testIncludeResourceDuplicatesError() throws Exception {
 				"@jar/jarA.jar!/META-INF/services/*, @jar/jarB.jar!/META-INF/services/*;onduplicate:=ERROR");
 			Jar jar = a.build();
 			assertFalse(a.check());
-			assertEquals("Duplicate file: META-INF/services/foo", a.getErrors()
+			assertEquals("includeresource.duplicates: duplicate found for path META-INF/services/foo", a.getErrors()
 				.get(0));
 
 			assertTrue(jar.getDirectories()
@@ -322,7 +322,7 @@ public void testIncludeResourceDuplicatesWarning() throws Exception {
 				"@jar/jarA.jar!/META-INF/services/*, @jar/jarB.jar!/META-INF/services/*;onduplicate:=WARN");
 			Jar jar = a.build();
 			assertFalse(a.check());
-			assertEquals("Duplicate file: META-INF/services/foo", a.getWarnings()
+			assertEquals("includeresource.duplicates: duplicate found for path META-INF/services/foo", a.getWarnings()
 				.get(0));
 
 			assertTrue(jar.getDirectories()
@@ -387,7 +387,7 @@ public void testIncludeResourceLiteralDuplicatesMerge(@InjectTemporaryDirectory
 			b.getJar()
 				.writeFolder(tmp);
 
-			assertEquals("b", IO.collect(IO.getFile(tmp, "a/a.txt")));
+			assertEquals("a", IO.collect(IO.getFile(tmp, "a/a.txt")));
 		}
 	}
 
@@ -416,7 +416,7 @@ public void testIncludeResourceLiteralDuplicatesError(@InjectTemporaryDirectory
 			b.setIncludeResource("/a/a.txt;literal='a', /a/a.txt;literal='b';onduplicate:=ERROR");
 			b.build();
 			assertFalse(b.check());
-			assertEquals("Duplicate file: /a/a.txt", b.getErrors()
+			assertEquals("includeresource.duplicates: duplicate found for path /a/a.txt", b.getErrors()
 				.get(0));
 
 			b.getJar()
@@ -461,12 +461,12 @@ public void testIncludeResourceDuplicatesMergeWithoutPlugin() throws Exception {
 				.containsKey("META-INF/services"));
 
 			Resource resource = jar.getResource("META-INF/services/foo");
-			// we expect OVERWRITE because there is no plugin with the tag
+			// we expect nothing because there is no plugin with the tag
 			// 'nonexistingtag'
 			// which means we have nothing which can merge META-INF/services
 			// files.
-			// so the default OVERWRITE behavior applies
-			assertEquals("b", IO.collect(resource.openInputStream()));
+			// so we keep the existing file
+			assertEquals("a", IO.collect(resource.openInputStream()));
 
 		}
 
@@ -507,12 +507,12 @@ public void testIncludeResourceDuplicatesTagWithoutStrategyEnumButNonExistingTag
 				.containsKey("META-INF/services"));
 
 			Resource resource = jar.getResource("META-INF/services/foo");
-			// we expect OVERWRITE because there is no plugin with the tag
+			// we expect nothing because there is no plugin with the tag
 			// 'nonexistingtag'
 			// which means we have nothing which can merge META-INF/services
 			// files.
-			// so the default OVERWRITE behavior applies
-			assertEquals("b", IO.collect(resource.openInputStream()));
+			// so we keep the existing file
+			assertEquals("a", IO.collect(resource.openInputStream()));
 
 		}
 	}
@@ -527,7 +527,7 @@ public void testIncludeResourceDuplicatesMergeWithTagAndWarn() throws Exception
 				"@jar/jarA.jar!/META-INF/services/*, @jar/jarB.jar!/META-INF/services/*;onduplicate:='MERGE,metainfservices,WARN'");
 			Jar jar = a.build();
 			assertFalse(a.check());
-			assertEquals("Duplicate file: META-INF/services/foo", a.getWarnings()
+			assertEquals("includeresource.duplicates: duplicate found for path META-INF/services/foo", a.getWarnings()
 				.get(0));
 
 			assertTrue(jar.getDirectories()