fix: adding properties after partial properties now works

This was thirowing an illegal state exception because the code assumed
that any previous property had to end in a VALUE. But this didn't take
into account partial properties that either don't have a value or don't
even have a separator (=).

Author: quintesse

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

@@ -393,8 +393,14 @@ private Cursor addNewKeyValue(String rawKey, String key, String rawValue, String
         while (pos.isType(PropertiesParser.Type.WHITESPACE, PropertiesParser.Type.COMMENT)) {
             pos.prev();
         }
-        // Make sure we're either at the start or we've found a VALUE
-        validate(pos.atStart() || pos.isType(PropertiesParser.Type.VALUE), pos);
+        // Make sure we're either at the start or we've found a property
+        validate(
+                pos.atStart()
+                        || pos.isType(
+                                PropertiesParser.Type.VALUE,
+                                PropertiesParser.Type.SEPARATOR,
+                                PropertiesParser.Type.KEY),
+                pos);
         // Add a newline whitespace token if necessary
         if (pos.hasToken()) {
             pos.next();

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

@@ -510,6 +510,28 @@ void testPutNewTest3() throws IOException, URISyntaxException {
         assertThat(sw.toString()).isEqualTo(readAll(getResource("/test3-putnew.properties")));
     }
 
+    @Test
+    void testPutNewAfterKey() throws IOException, URISyntaxException {
+        Path f = getResource("/test-keyatend.properties");
+        Properties p = Properties.loadProperties(f);
+        p.put("five", "5");
+        StringWriter sw = new StringWriter();
+        p.store(sw);
+        assertThat(sw.toString())
+                .isEqualTo(readAll(getResource("/test-keyatend-putnew.properties")));
+    }
+
+    @Test
+    void testPutNewAfterSeparator() throws IOException, URISyntaxException {
+        Path f = getResource("/test-separatoratend.properties");
+        Properties p = Properties.loadProperties(f);
+        p.put("five", "5");
+        StringWriter sw = new StringWriter();
+        p.store(sw);
+        assertThat(sw.toString())
+                .isEqualTo(readAll(getResource("/test-separatoratend-putnew.properties")));
+    }
+
     @Test
     void testPutFirstWithHeader() throws IOException, URISyntaxException {
         try (StringReader sr = new StringReader("# A header comment")) {

src/test/resources/test-keyatend-putnew.properties

@@ -0,0 +1,18 @@
+#comment1
+#  comment2
+
+! comment3
+one=simple
+two=value containing spaces
+# another comment
+! and a comment
+! block
+three=and escapes\n\t\r\f
+\ with\ spaces   =    everywhere  
+altsep:value
+multiline = one \
+    two  \
+	three
+key.4 = \u1234ሴ
+key.at.end
+five=5

src/test/resources/test-keyatend.properties

@@ -0,0 +1,17 @@
+#comment1
+#  comment2
+
+! comment3
+one=simple
+two=value containing spaces
+# another comment
+! and a comment
+! block
+three=and escapes\n\t\r\f
+\ with\ spaces   =    everywhere  
+altsep:value
+multiline = one \
+    two  \
+	three
+key.4 = \u1234ሴ
+key.at.end

src/test/resources/test-separatoratend-putnew.properties

@@ -0,0 +1,18 @@
+#comment1
+#  comment2
+
+! comment3
+one=simple
+two=value containing spaces
+# another comment
+! and a comment
+! block
+three=and escapes\n\t\r\f
+\ with\ spaces   =    everywhere  
+altsep:value
+multiline = one \
+    two  \
+	three
+key.4 = \u1234ሴ
+separator.at.end=
+five=5

src/test/resources/test-separatoratend.properties

@@ -0,0 +1,17 @@
+#comment1
+#  comment2
+
+! comment3
+one=simple
+two=value containing spaces
+# another comment
+! and a comment
+! block
+three=and escapes\n\t\r\f
+\ with\ spaces   =    everywhere  
+altsep:value
+multiline = one \
+    two  \
+	three
+key.4 = \u1234ሴ
+separator.at.end=