Testing how Java's proxy settings behave

ProxyTest.java

import com.google.common.collect.ImmutableList;
import org.junit.Test;
import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertThat;

import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.ProxySelector;
import java.net.URISyntaxException;

public class ProxyTest {

    private void proxySettings(String httpProxy, String httpsProxy, String nonProxyHosts) {
        if (httpProxy == null)
            System.clearProperty("http.proxyHost");
        else
            System.setProperty("http.proxyHost", httpProxy);

        if (httpsProxy == null)
            System.clearProperty("https.proxyHost");
        else
            System.setProperty("https.proxyHost", httpsProxy);

        if (nonProxyHosts == null)
            System.clearProperty("http.nonProxyHosts");
        else
            System.setProperty("http.nonProxyHosts", nonProxyHosts);
    }

    @Test
    public void withoutAProxyGoesDirect() throws URISyntaxException {
        proxySettings(null, null, null);
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        java.util.List proxies = selector.select(new java.net.URI("https://example.com"));
        assertEquals(proxies.size(), 1);
        assertThat(ImmutableList.of(Proxy.NO_PROXY), is(proxies));
    }

    @Test
    public void usesAHttpProxyForHttpUrlsOnly() throws URISyntaxException {
        proxySettings("proxy.example.com",null, null);
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("https://example.com")));
    }

    @Test
    public void usesAHttpsProxyForHttpsUrlsOnly() throws URISyntaxException {
        proxySettings(null, "proxy.example.com",null);
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 443))), selector.select(new java.net.URI("https://example.com")));
    }

    @Test
    public void avoidsProxyForLocalhostByDefault() throws URISyntaxException {
        proxySettings("proxy.example.com",null, null);
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://localhost")));
    }

    @Test
    public void canBypassProxy() throws URISyntaxException {
        proxySettings("proxy.example.com",null, "example.com");
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.org")));
    }

    @Test
    public void canBypassProxyForMultipleHosts() throws URISyntaxException {
        proxySettings("proxy.example.com",null, "example.com|example.org");
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://example.org")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://subdomain.example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.net")));
    }

    @Test
    public void canBypassProxyForMultipleHostPatterns() throws URISyntaxException {
        proxySettings("proxy.example.com",null, "*.example.com|*.example.org");
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.org")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://subdomain.example.com")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://subdomain.example.org")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.net")));
    }

    @Test
    public void canBypassProxyForPartialHostPatterns() throws URISyntaxException {
        proxySettings("proxy.example.com",null, "*-internal.example.com");
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.org")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://a-internal.example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://-internal.example.com")));
    }

    @Test
    public void canBypassProxyForMultiplePartialHostPatterns() throws URISyntaxException {
        proxySettings("proxy.example.com",null, "*-internal.example.com|*.foo.example.com");
        ProxySelector selector = new sun.net.spi.DefaultProxySelector();
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://example.org")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://a-internal.example.com")));
        assertEquals(ImmutableList.of(Proxy.NO_PROXY), selector.select(new java.net.URI("http://bar.foo.example.com")));
        assertEquals(ImmutableList.of(new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 80))), selector.select(new java.net.URI("http://-internal.example.com")));
    }
}