Add simple unit tests

src/test/java/org/jabref/logic/formatter/bibtexfields/CleanupUrlFormatterTest.java

@@ -29,6 +29,12 @@ void extractURLFormLink() {
                 formatter.format("away.php?to=http%3A%2F%2Fwikipedia.org&a=snippet"));
     }
 
+    @Test
+    void validURLUnmodified() {
+        // the caller has to pay attention that this does not happen
+        assertEquals("http://wikipedia.org", formatter.format("http://wikipedia.org"));
+    }
+
     @Test
     void latexCommandsNotRemoved() {
         assertEquals("http://pi.informatik.uni-siegen.de/stt/36\\_2/./03\\_Technische\\_Beitraege/ZEUS2016/beitrag\\_2.pdf", formatter.format("http://pi.informatik.uni-siegen.de/stt/36\\_2/./03\\_Technische\\_Beitraege/ZEUS2016/beitrag\\_2.pdf"));

src/test/java/org/jabref/logic/formatter/bibtexfields/RemoveHyphenatedNewlinesFormatterTest.java

@@ -20,6 +20,11 @@ public void removeHyphensBeforeNewlines() {
         assertEquals("water", formatter.format("wa-\rter"));
     }
 
+    @Test
+    public void withoutHyphensUnmodified() {
+        assertEquals("water", formatter.format("water"));
+    }
+
     @Test
     public void removeHyphensBeforePlatformSpecificNewlines() {
         String newLine = String.format("%n");

src/test/java/org/jabref/logic/formatter/bibtexfields/RemoveNewlinesFormatterTest.java

@@ -30,6 +30,11 @@ public void removeLineFeed() {
         assertEquals("n linebreak", formatter.format("n\nlinebreak"));
     }
 
+    @Test
+    public void withoutNewLineUnmodified() {
+        assertEquals("no linebreak", formatter.format("no linebreak"));
+    }
+
     @Test
     public void removePlatformSpecificNewLine() {
         String newLine = String.format("%n");

src/test/java/org/jabref/logic/formatter/casechanger/LowerCaseFormatterTest.java

@@ -19,6 +19,7 @@ public void setUp() {
 
     @Test
     public void test() {
+        assertEquals("lower", formatter.format("lower"));
         assertEquals("lower", formatter.format("LOWER"));
         assertEquals("lower {UPPER}", formatter.format("LOWER {UPPER}"));
         assertEquals("lower {U}pper", formatter.format("LOWER {U}PPER"));

src/test/java/org/jabref/logic/layout/format/RemoveBracketsTest.java

@@ -34,4 +34,9 @@ public void singleClosingBraceCorrectlyRemoved() throws Exception {
     public void bracePairWithEscapedBackslashCorrectlyRemoved() throws Exception {
         assertEquals("\\some text\\", formatter.format("\\{some text\\}"));
     }
+
+    @Test
+    public void withoutBracketsUnmodified() throws Exception {
+        assertEquals("some text", formatter.format("some text"));
+    }
 }