.flatMap(Function.identity())
                .collect(toSet());
    }

    /**
     * Check whether the required profiles were found in any of the projects we're building or the settings.
     * @param session the Maven session.
     * @param profileActivation the requested optional and required profiles.
     */

        // TODO Copied from the DefaultInterpolator. We likely want to resurrect the PathTranslator or at least a
        // similar component for re-usage
        if (file != null) {
            if (file.isAbsolute()) {
                // path was already absolute, just normalize file separator and we're done
            } else if (file.getPath().startsWith(File.separator)) {

** Testing mojos

  This can be a problem if the tests are more than simple unit tests;
  that is, if they require configuration of a server process, and
  subsequent testing in-container.

  Since we're only going to concern ourselves with states where localhost is
  still active, we only need to worry about this case when the server container
  is <<not>> installed on localhost. This allows the popular pattern of starting

                "<packaging>pom</packaging><properties><addedProperty>addedValue</addedProperty></properties>");
        Files.write(parent.toPath(), parentContent.getBytes(StandardCharsets.UTF_8));
        // re-build pom with modified parent
        ProjectBuildingResult result = projectBuilder.build(child, configuration);
        assertThat(result.getProject().getProperties(), hasKey((Object) "addedProperty"));
    }

    @Test