determinePotentialHostsForFragment(iu);

	}

	/**

	 * Determines all potential hosts for a fragment.

	 * A potential host is an IU that satisfies requirements specified for fragment.

	 *  

	 * @param iu an eventual fragment. It does nothing if IU is not a fragment or is null

	 */

	private void determinePotentialHostsForFragment(IInstallableUnit iu) {

		// determine matching hosts only for fragments

		if (!(iu instanceof IInstallableUnitFragment))

			return;

		IInstallableUnitFragment fragment = (IInstallableUnitFragment) iu;

		// for each host requirement, find matches and remember them 

		for (IRequirement req : fragment.getHost()) {

			List<IInstallableUnit> matches = getApplicableMatches(req);

			rememberHostMatches((IInstallableUnitFragment) iu, matches);

		}

import org.eclipse.equinox.p2.engine.IProvisioningPlan;

	/**

	 * Test that fragments does not affect the solution when the fragments do not have requirements.

	 * This mean that having a fragment that has a host requirement that cannot be satisfied it will not determine solver to fail to find a solution.

	 * This case is valid only in the context that bug #222157 is solved, meaning that host requirements are not supposed to be expressed also 

	 * as requirements (which was the case described also in #222158) 

	 * 

	 * This test does not include the host IU in request or metadata repository.

	 */

	public void testFragmentsOptionality1() {

		testFragmentsOptionality(false);

	}

	/**

	 * Test that fragments does not affect the solution when the fragments do not have requirements.

	 * This mean that having a fragment that has a host requirement that cannot be satisfied it will not determine solver to fail to find a solution.

	 * This case is valid only in the context that bug #222157 is solved, meaning that host requirements are not supposed to be expressed also 

	 * as requirements (which was the case described also in #222158) 

	 * 

	 * This test does not include the host IU in request but it includes it in metadata repository.

	 */

	public void testFragmentsOptionality2() {

		testFragmentsOptionality(true);

	}

	private void testFragmentsOptionality(boolean includeHostIUInRepository) {

		String ID1 = "iu.test1";

		String ID2 = "iu.test2";

		String ID3 = "iuFragment.test3";

		IInstallableUnit iu1 = createEclipseIU(ID1);

		IInstallableUnit iu2 = createEclipseIU(ID2);

		IInstallableUnit iu3 = createIUFragment(iu1, ID3, DEFAULT_VERSION);

		ProfileChangeRequest req = new ProfileChangeRequest(createProfile(getName()));

		req.addAll(Arrays.asList(iu2, iu3));

		if (includeHostIUInRepository) {

			createTestMetdataRepository(new IInstallableUnit[] {iu1, iu2, iu3});

		} else {

			createTestMetdataRepository(new IInstallableUnit[] {iu2, iu3});

		}

		IProvisioningPlan provisioningPlan = createPlanner().getProvisioningPlan(req, null, null);

		{

			Iterator<IInstallableUnit> iterator = provisioningPlan.getAdditions().query(QueryUtil.createIUQuery(ID1), null).iterator();

			assertTrue("IU " + ID1 + " not expected as part of solution", !iterator.hasNext());

		}

		{

			Iterator<IInstallableUnit> iterator = provisioningPlan.getAdditions().query(QueryUtil.createIUQuery(ID2), null).iterator();

			assertTrue("IU " + ID2 + " expected as part of solution", iterator.hasNext());

			assertEquals("Number of fragments", 0, iterator.next().getFragments().size());

		}

		{

			Iterator<IInstallableUnit> iterator = provisioningPlan.getAdditions().query(QueryUtil.createIUQuery(ID3), null).iterator();

			assertTrue("IU " + ID3 + " expected as part of solution", iterator.hasNext());

			assertEquals("Number of fragments", 0, iterator.next().getFragments().size());

		}

	}