@Test
    public void applicableWhenIgnoringUserPropertiesAndConfigured() {
        Mockito
            .doReturn("autoIgnoringUserProperties")
            .when(TestcontainersConfiguration.getInstance())
            .getEnvVarOrProperty(eq("dockerconfig.source"), anyString());

        Properties oldProperties = System.getProperties();
        try {
            System.setProperty("DOCKER_HOST", "tcp://1.2.3.4:2375");
            EnvironmentAndSystemPropertyClientProviderStrategy strategy = new EnvironmentAndSystemPropertyClientProviderStrategy();

            assertThat(strategy.isApplicable()).isTrue();
        } finally {
            System.setProperties(oldProperties);
        }
    }
Test that we can use Testcontainers configuration file to override settings. We assume that docker-java has test
coverage for detection of environment variables (e.g. DOCKER_HOST) and its own properties config file.
core/src/test/java/org/testcontainers/dockerclient/EnvironmentAndSystemPropertyClientProviderStrategyTest.java