Enable extra warnings

Author: thomasleplus

pom.xml

@@ -139,6 +139,10 @@
           <release>${java.minVersion}</release>
           <showDeprecation>true</showDeprecation>
           <showWarnings>true</showWarnings>
+          <compilerArgs>
+            <arg>-Xlint:all</arg>
+            <arg>-Werror</arg>
+          </compilerArgs>
         </configuration>
       </plugin>
       <plugin>

src/test/java/org/leplus/xslt/TestXSLT.java

@@ -86,9 +86,9 @@ private void testXSLT(final File xsltFile, final File inputFile, final File expe
 			throws TransformerException, SAXException, IOException {
 		final File actualOutputFile = applyXSLT(inputFile, xsltFile);
 		final String type = Files.probeContentType(actualOutputFile.toPath());
-		if (type.startsWith(XML) || type.endsWith(XML)) {
+		if (type != null && (type.startsWith(XML) || type.endsWith(XML))) {
 			compareXML(expectedOutputFile, actualOutputFile);
-		} else if (type.startsWith(JSON) || type.endsWith(JSON)) {
+		} else if (type != null && (type.startsWith(JSON) || type.endsWith(JSON))) {
 			compareJSON(expectedOutputFile, actualOutputFile);
 		} else {
 			compareFile(expectedOutputFile, actualOutputFile);