diff --git a/container-tests/src/test/java/okhttp3/containers/BasicProxyTest.kt b/container-tests/src/test/java/okhttp3/containers/BasicProxyTest.kt
new file mode 100644
index 000000000000..01f2b5e78690
--- /dev/null
+++ b/container-tests/src/test/java/okhttp3/containers/BasicProxyTest.kt
@@ -0,0 +1,208 @@
+package okhttp3.containers
+
+import assertk.assertThat
+import assertk.assertions.contains
+import assertk.assertions.isEqualTo
+import java.net.HttpURLConnection
+import java.net.Proxy
+import java.net.URI
+import javax.net.ssl.HttpsURLConnection
+import okhttp3.HttpUrl.Companion.toHttpUrl
+import okhttp3.OkHttpClient
+import okhttp3.Protocol
+import okhttp3.Request
+import okhttp3.containers.BasicMockServerTest.Companion.MOCKSERVER_IMAGE
+import okhttp3.containers.BasicMockServerTest.Companion.trustMockServer
+import okio.buffer
+import okio.source
+import org.junit.jupiter.api.Disabled
+import org.junit.jupiter.api.Test
+import org.mockserver.client.MockServerClient
+import org.mockserver.configuration.Configuration
+import org.mockserver.logging.MockServerLogger
+import org.mockserver.model.HttpRequest.request
+import org.mockserver.model.HttpResponse.response
+import org.mockserver.proxyconfiguration.ProxyConfiguration
+import org.mockserver.socket.tls.KeyStoreFactory
+import org.testcontainers.containers.MockServerContainer
+import org.testcontainers.junit.jupiter.Container
+import org.testcontainers.junit.jupiter.Testcontainers
+
+@Testcontainers
+class BasicProxyTest {
+  @Container
+  val mockServer: MockServerContainer =
+    MockServerContainer(MOCKSERVER_IMAGE)
+      .withNetworkAliases("mockserver")
+
+  @Test
+  fun testOkHttpDirect() {
+    testRequest {
+      val client = OkHttpClient()
+
+      val response =
+        client.newCall(
+          Request((mockServer.endpoint + "/person?name=peter").toHttpUrl()),
+        ).execute()
+
+      assertThat(response.body.string()).contains("Peter the person")
+      assertThat(response.protocol).isEqualTo(Protocol.HTTP_1_1)
+    }
+  }
+
+  @Test
+  fun testOkHttpProxied() {
+    testRequest {
+      it.withProxyConfiguration(ProxyConfiguration.proxyConfiguration(ProxyConfiguration.Type.HTTP, it.remoteAddress()))
+
+      val client =
+        OkHttpClient.Builder()
+          .proxy(Proxy(Proxy.Type.HTTP, it.remoteAddress()))
+          .build()
+
+      val response =
+        client.newCall(
+          Request((mockServer.endpoint + "/person?name=peter").toHttpUrl()),
+        ).execute()
+
+      assertThat(response.body.string()).contains("Peter the person")
+    }
+  }
+
+  @Test
+  fun testOkHttpSecureDirect() {
+    testRequest {
+      val client =
+        OkHttpClient.Builder()
+          .trustMockServer()
+          .build()
+
+      val response =
+        client.newCall(
+          Request((mockServer.secureEndpoint + "/person?name=peter").toHttpUrl()),
+        ).execute()
+
+      assertThat(response.body.string()).contains("Peter the person")
+      assertThat(response.protocol).isEqualTo(Protocol.HTTP_2)
+    }
+  }
+
+  @Test
+  fun testOkHttpSecureProxiedHttp1() {
+    testRequest {
+      val client =
+        OkHttpClient.Builder()
+          .trustMockServer()
+          .proxy(Proxy(Proxy.Type.HTTP, it.remoteAddress()))
+          .protocols(listOf(Protocol.HTTP_1_1))
+          .build()
+
+      val response =
+        client.newCall(
+          Request((mockServer.secureEndpoint + "/person?name=peter").toHttpUrl()),
+        ).execute()
+
+      assertThat(response.body.string()).contains("Peter the person")
+      assertThat(response.protocol).isEqualTo(Protocol.HTTP_1_1)
+    }
+  }
+
+  @Test
+  @Disabled("https://github.com/square/okhttp/issues/8233")
+  fun testOkHttpSecureProxiedHttp2() {
+    testRequest {
+      val client =
+        OkHttpClient.Builder()
+          .trustMockServer()
+          .proxy(Proxy(Proxy.Type.HTTP, it.remoteAddress()))
+          .protocols(listOf(Protocol.HTTP_2, Protocol.HTTP_1_1))
+          .build()
+
+      val response =
+        client.newCall(
+          Request((mockServer.secureEndpoint + "/person?name=peter").toHttpUrl()),
+        ).execute()
+
+      assertThat(response.body.string()).contains("Peter the person")
+      assertThat(response.protocol).isEqualTo(Protocol.HTTP_2)
+    }
+  }
+
+  @Test
+  fun testUrlConnectionDirect() {
+    testRequest {
+      val url = URI(mockServer.endpoint + "/person?name=peter").toURL()
+
+      val connection = url.openConnection() as HttpURLConnection
+
+      assertThat(connection.inputStream.source().buffer().readUtf8()).contains("Peter the person")
+    }
+  }
+
+  @Test
+  fun testUrlConnectionPlaintextProxied() {
+    testRequest {
+      val proxy =
+        Proxy(
+          Proxy.Type.HTTP,
+          it.remoteAddress(),
+        )
+
+      val url = URI(mockServer.endpoint + "/person?name=peter").toURL()
+
+      val connection = url.openConnection(proxy) as HttpURLConnection
+
+      assertThat(connection.inputStream.source().buffer().readUtf8()).contains("Peter the person")
+    }
+  }
+
+  @Test
+  fun testUrlConnectionSecureDirect() {
+    val keyStoreFactory = KeyStoreFactory(Configuration.configuration(), MockServerLogger())
+    HttpsURLConnection.setDefaultSSLSocketFactory(keyStoreFactory.sslContext().socketFactory)
+
+    testRequest {
+      val url = URI(mockServer.secureEndpoint + "/person?name=peter").toURL()
+
+      val connection = url.openConnection() as HttpURLConnection
+
+      assertThat(connection.inputStream.source().buffer().readUtf8()).contains("Peter the person")
+    }
+  }
+
+  @Test
+  fun testUrlConnectionSecureProxied() {
+    val keyStoreFactory = KeyStoreFactory(Configuration.configuration(), MockServerLogger())
+    HttpsURLConnection.setDefaultSSLSocketFactory(keyStoreFactory.sslContext().socketFactory)
+
+    testRequest {
+      val proxy =
+        Proxy(
+          Proxy.Type.HTTP,
+          it.remoteAddress(),
+        )
+
+      val url = URI(mockServer.secureEndpoint + "/person?name=peter").toURL()
+
+      val connection = url.openConnection(proxy) as HttpURLConnection
+
+      assertThat(connection.inputStream.source().buffer().readUtf8()).contains("Peter the person")
+    }
+  }
+
+  private fun testRequest(function: (MockServerClient) -> Unit) {
+    MockServerClient(mockServer.host, mockServer.serverPort).use { mockServerClient ->
+      val request =
+        request().withPath("/person")
+          .withQueryStringParameter("name", "peter")
+
+      mockServerClient
+        .`when`(
+          request,
+        )
+        .respond(response().withBody("Peter the person!"))
+
+      function(mockServerClient)
+    }
+  }
+}