fix: normalize keeps absolute paths absolute (#403)

fixes #292

Author: markjschreiber

src/main/java/software/amazon/nio/spi/s3/S3Path.java

@@ -387,6 +387,10 @@ public S3Path normalize() {
         final var elements = pathRepresentation.elements();
         final var realElements = new LinkedList<String>();
 
+        if (this.isAbsolute()) {
+            realElements.add(PATH_SEPARATOR);
+        }
+
         for (var element : elements) {
             if (element.equals(".")) {
                 continue;

src/test/java/software/amazon/nio/spi/s3/S3PathTest.java

@@ -278,6 +278,18 @@ public void normalize() {
         assertEquals(fileSystem.getPath("/dir3/"), relativeDirectory.toAbsolutePath().normalize());
     }
 
+    @Test
+    public void normalizeAndIsAbsolute() {
+        final S3Path pathRelative = S3Path.getPath(fileSystem, "foo/./baa/");
+        final S3Path pathAbsolute = S3Path.getPath(fileSystem, "/foo/./baa/");
+
+        assertFalse(pathRelative.isAbsolute());
+        assertTrue(pathAbsolute.isAbsolute());
+
+        assertFalse(pathRelative.normalize().isAbsolute());
+        assertTrue(pathAbsolute.normalize().isAbsolute());
+    }
+
     @Test
     public void resolve() {
         assertEquals(absoluteObject, root.resolve(absoluteObject));