fix: drop a backslash at the end of the input

src/main/java/org/codejive/properties/PropertiesParser.java

@@ -272,6 +272,10 @@ private void addChar(int ch) throws IOException {
         if (ch == '\\') {
             hasEscapes = true;
             int ch2 = readChar();
+            if (isEof(ch2)) {
+                // A backslash at the end of the input escapes nothing
+                return;
+            }
             str.append((char) ch2);
             if (ch2 == 'u') {
                 for (int i = 0; i < 4; i++) {
@@ -315,6 +319,9 @@ public static String unescape(String escape) {
         for (int i = 0; i < escape.length(); i++) {
             char ch = escape.charAt(i);
             if (ch == '\\') {
+                if (i == escape.length() - 1) {
+                    break;
+                }
                 ch = escape.charAt(++i);
                 switch (ch) {
                     case 't':

src/test/java/org/codejive/properties/TestPropertiesParser.java

@@ -131,4 +131,16 @@ void testMissingSeparatorAndValueAtEof() throws IOException {
                         new Token(Type.SEPARATOR, ""),
                         new Token(Type.VALUE, ""));
     }
+
+    @Test
+    void testBackslashAtEof() throws IOException {
+        List<Token> tokens =
+                PropertiesParser.tokens(new StringReader("foo=bar\\")).collect(Collectors.toList());
+
+        assertThat(tokens)
+                .containsExactly(
+                        new Token(Type.KEY, "foo"),
+                        new Token(Type.SEPARATOR, "="),
+                        new Token(Type.VALUE, "bar\\", "bar"));
+    }
 }