DCA11Y-1145: Fix unreadable version file exception message to include…

… "not"

frontend-plugin-core/src/main/java/com/github/eirslett/maven/plugins/frontend/lib/NodeVersionDetector.java

@@ -88,9 +88,7 @@ public static String recursivelyFindVersion(File directory) throws Exception {
     }
 
     private static String readNvmrcFile(File nvmrcFile, Path nvmrcFilePath, Logger logger) throws Exception {
-        if (!nvmrcFile.canRead()) {
-            throw new Exception("Tried to read the node version from the file, but giving up because it's possible to read" + nvmrcFile.getPath());
-        }
+        assertNodeVersionFileIsReadable(nvmrcFile);
 
         List<String> lines = Files.readAllLines(nvmrcFilePath);
         Optional<String> version = readNvmrcFileLines(lines);
@@ -134,9 +132,7 @@ static Optional<String> readNvmrcFileLines(List<String> lines) {
     }
 
     private static String readToolVersionsFile(File toolVersionsFile, Path toolVersionsFilePath, Logger logger) throws Exception {
-        if (!toolVersionsFile.canRead()) {
-            throw new Exception("Tried to read the node version from the file, but giving up because it's possible to read" + toolVersionsFile.getPath());
-        }
+        assertNodeVersionFileIsReadable(toolVersionsFile);
 
         List<String> lines = Files.readAllLines(toolVersionsFilePath);
         for (String line: lines) {
@@ -157,4 +153,10 @@ private static String readToolVersionsFile(File toolVersionsFile, Path toolVersi
         }
         return null;
     }
+
+    private static void assertNodeVersionFileIsReadable(File file) throws Exception {
+        if (!file.canRead()) {
+            throw new Exception("Tried to read the node version from the file, but giving up because it's not possible to read" + file.getPath());
+        }
+    }
 }