Fix FinalTip#hashcode() and TipProviderTest#testGetNextTip() #1148

The test case org.eclipse.tips.core.TipProviderTest#testGetNextTip()
randomly fails because it checks that the read state of a tip after
being set can properly be retrieved. This functionality relies on the
hash code of tips staying the same, but the one for the FinalTip
currently changes if the system time has changed, as it re-calculates
the creation time used for the calculation of the hash code on every
access.

With this change, the creation time for the FinalTip is stored such that
its hash code does not change. This also fixes the according test case.

Fixes #1148

Author: HeikoKlare

ua/org.eclipse.tips.core/src/org/eclipse/tips/core/internal/FinalTip.java

@@ -31,17 +31,16 @@ public class FinalTip extends Tip implements IHtmlTip {
 	private static final String EH1 = "</h1>"; //$NON-NLS-1$
 	private static final String H1 = "<h1>"; //$NON-NLS-1$
 
-	/**
-	 * Constructor.
-	 */
+	private final Date creationDate;
+
 	public FinalTip(String providerId) {
 		super(providerId);
+		this.creationDate = Calendar.getInstance().getTime();
 	}
 
 	@Override
 	public Date getCreationDate() {
-		Calendar instance = Calendar.getInstance();
-		return instance.getTime();
+		return creationDate;
 	}
 
 	@Override

ua/org.eclipse.tips.tests/src/org/eclipse/tips/core/TipProviderTest.java

@@ -96,6 +96,7 @@ public void testGetCurrentTip2() {
 	@Test
 	public void testGetNextTip() {
 		createTestData();
+		assertEquals(fProvider.getCurrentTip(), fProvider.getNextTip());
 		fManager.setAsRead(fProvider.getNextTip());
 		assertNotEquals(fProvider.getCurrentTip(), fProvider.getNextTip());
 		Tip nextTip = fProvider.getNextTip();