### Question:
TfVarFilesOptionFormatter implements TfOptionFormatter { public String convert(String format, Object value) { String str = ""; if (value instanceof String) { str = csvConverter("-var-file=%s ", (String) value); } return str; }  String convert(String format, Object value);  }### Answer:
@Test public void convertTfVarFilesCsvOneFile() throws TerraformException { String format = "-var-file"; String value = "test1.txt "; Assert.assertEquals(formatter.convert(format, value), "-var-file=test1.txt "); }
@Test public void convertTfVarFilesCsvManyFiles() throws TerraformException { String format = "-var-file"; String value = "test1.txt, test2.txt,test3.txt"; Assert.assertEquals(formatter.convert(format, value), "-var-file=test1.txt -var-file=test2.txt -var-file=test3.txt "); }