Unit Tests
The first step in refactoring is to create unit tests that verify the basic functionality. If you're doing Extreme Programming (XP) with incremental, test-first programming, those tests exist already as a by-product of that process.
The following test requires a file named template.html that contains the text "xxx%CODE%yyy%ALTCODE%zzz".
import java.io.*;
import junit.framework.*;
public class CodeReplacerTest extends TestCase {
CodeReplacer replacer;
public CodeReplacerTest(String testName){super(testName);}
protected void setUp() {replacer = new CodeReplacer();}
public void testTemplateLoadedProperly() {
try {
replacer.substitute("ignored",
new PrintWriter(new StringWriter()));
} catch (Exception ex) {
fail("No exception expected, but saw:" + ex);
}
assertEquals("xxx%CODE%yyy%ALTCODE%zzz\n",
replacer.sourceTemplate);
}
public void testSubstitution() {
StringWriter stringOut = new StringWriter();
PrintWriter testOut = new PrintWriter (stringOut);
String trackingId = "01234567";
try {
replacer.substitute(trackingId, testOut);
} catch (IOException ex) {
fail ("testSubstitution exception - " + ex);
}
assertEquals("xxx01234567yyy01234-567zzz\n",
stringOut.toString());
}
}
This code uses the JUnit unit-testing framework introduced in the previous chapter.