given:
        def jdk8 = createJdkInstallation("8")
        def jdk11 = createJdkInstallation("11")
        def jdk15 = createJdkInstallation("15")

        when:
        def registry = createRegistry([jdk8, jdk11, jdk15])
        def installations = registry.listInstallations()

        then:
        installations.size() == 3
        installations*.location.containsAll(jdk8, jdk11, jdk15)