JoinerTest.java

    @Test
    public void testJoiner() throws Exception {
        List<String> texts = Lists.newArrayList("eins", null, "drei", "vier", "fünf", "sechs", "sieben", null);
        String joined;
        String expected;
        
        joined = Joiner.on(";")
                .skipNulls()
                .join(texts);

        expected = "eins;drei;vier;fünf;sechs;sieben";

        assertThat(joined, is(expected));

        joined = Joiner.on(";")
                .useForNull("MISSING")
                .join(texts);

        expected = "eins;MISSING;drei;vier;fünf;sechs;sieben;MISSING";
     
        assertThat(joined, is(expected));
    }

JoinerWithClassesThatImplementAppendeableInterfaceTest.java

    @Test
    public void testJoinerWithClassesThatImplementAppendeableInterface() throws Exception {
        List<String> texts = Lists.newArrayList("1000200030004", "Apple", "MacBook Pro", null, "false");

        File file = File.createTempFile("guava","study");
        FileWriter fileWriter = new FileWriter(file);

        Joiner.on(";")
                .useForNull("N/A")
                .appendTo(fileWriter, texts);
        fileWriter.close();

        FileReader fileReader = new FileReader(file);
        BufferedReader reader = new BufferedReader(fileReader);
        String csvLine = reader.readLine();
        reader.close();
        String expected = "1000200030004;Apple;MacBook Pro;N/A;false";
        assertThat(csvLine, is(expected));

        file.delete();
    }

JoinerWithStringBuilderTest.java

    @Test
    public void testJoinerWithStringBuilder() throws Exception {
        List<String> texts = Lists.newArrayList("Never", "change", "a", null, "system");

        StringBuilder sb = new StringBuilder();

        Joiner.on(" ")
                .useForNull("__________")
                .appendTo(sb, texts);

        String expected = "Never change a __________ system";
        
        assertThat(sb.toString(), is(expected));

    }

MapJoinerTest.java

   @Test
    public void testMapJoiner() throws Exception {
      
        Map<String,String> map = Maps.newLinkedHashMap();
        map.put("Audi", "Neckarsulm");
        map.put("VW", "Wolfsburg");
        map.put("Merzedes", "Stuttgart");
        map.put("Porsche", "Stuttgart");
        map.put("Opel", "Rüsselsheim");
        map.put("Ford", "Köln");

        String joined = Joiner.on("#").withKeyValueSeparator("=").join(map);
        String expected = "Audi=Neckarsulm#VW=Wolfsburg#Merzedes=Stuttgart#Porsche=Stuttgart#Opel=Rüsselsheim#Ford=Köln";

        assertThat(joined, is(expected));
   }