Use input stream as error stream when necessary (#14)

- Use inputStream as errorStream when errored response code (as Sun intended a million years ago)
- Unit test to check error stream

src/main/java/com/easypost/easyvcr/clients/httpurlconnection/RecordableHttpURLConnection.java

@@ -706,8 +706,33 @@ public Permission getPermission() throws IOException {
      */
     @Override
     public InputStream getErrorStream() {
-        // not in cassette, get from real request
-        return this.connection.getErrorStream();
+        if (mode == Mode.Bypass) {
+            return this.connection.getErrorStream();
+        }
+
+        /*
+        Based on this Sun source code for HttpURLConnection (seen below):
+        if (connected && responseCode >= 400) {
+            // Client Error 4xx and Server Error 5xx
+            if (errorStream != null) {
+                return errorStream;
+            } else if (inputStream != null) {
+                return inputStream;
+            }
+        }
+        return null;
+         */
+        try {
+            buildCache();
+
+            if (this.cachedInteraction.getResponse().getStatus().getCode() >= 400) {
+                // Client Error 4xx and Server Error 5xx
+                return createInputStream(this.cachedInteraction.getResponse().getBody());
+            }
+            return null;
+        } catch (VCRException | RecordingExpirationException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     /**

src/main/java/com/easypost/easyvcr/clients/httpurlconnection/RecordableHttpsURLConnection.java

@@ -23,8 +23,10 @@
 import java.net.ProtocolException;
 import java.net.Proxy;
 import java.net.SocketPermission;
+import java.net.SocketTimeoutException;
 import java.net.URL;
 import java.net.UnknownServiceException;
+import java.nio.ByteBuffer;
 import java.security.Permission;
 import java.security.Principal;
 import java.security.cert.Certificate;
@@ -709,8 +711,33 @@ public Permission getPermission() throws IOException {
      */
     @Override
     public InputStream getErrorStream() {
-        // not in cassette, get from real request
-        return this.connection.getErrorStream();
+        if (mode == Mode.Bypass) {
+            return this.connection.getErrorStream();
+        }
+
+        /*
+        Based on this Sun source code for HttpURLConnection (seen below):
+        if (connected && responseCode >= 400) {
+            // Client Error 4xx and Server Error 5xx
+            if (errorStream != null) {
+                return errorStream;
+            } else if (inputStream != null) {
+                return inputStream;
+            }
+        }
+        return null;
+         */
+        try {
+            buildCache();
+
+            if (this.cachedInteraction.getResponse().getStatus().getCode() >= 400) {
+                // Client Error 4xx and Server Error 5xx
+                return createInputStream(this.cachedInteraction.getResponse().getBody());
+            }
+            return null;
+        } catch (VCRException | RecordingExpirationException e) {
+            throw new RuntimeException(e);
+        }
     }
 
     /**

src/test/java/FakeDataService.java

@@ -76,20 +76,26 @@ public RecordableHttpsURLConnection getClient(String url) throws Exception {
             throw new Exception("No VCR or client has been set.");
         }
 
-        @Override
         public IPAddressData getIPAddressData() throws Exception {
             RecordableHttpsURLConnection client = (RecordableHttpsURLConnection) getIPAddressDataRawResponse();
             String json = readFromInputStream(client.getInputStream());
 
             return Serialization.convertJsonToObject(json, IPAddressData.class);
         }
 
-        @Override
         public Object getIPAddressDataRawResponse() throws Exception {
             RecordableHttpsURLConnection client = getClient(URL);
             client.connect();
             return client;
         }
+
+        public RecordableHttpsURLConnection makeBadRequest() throws Exception {
+            RecordableHttpsURLConnection client = getClient(URL);
+            client.setRequestMethod("POST");
+            client.connect();
+
+            return client;
+        }
     }
 
     private static class FakeDataServiceBase {

src/test/java/HttpUrlConnectionTest.java

@@ -9,12 +9,14 @@
 import com.easypost.easyvcr.Mode;
 import com.easypost.easyvcr.RecordingExpirationException;
 import com.easypost.easyvcr.TimeFrame;
+import com.easypost.easyvcr.Utilities;
 import com.easypost.easyvcr.clients.httpurlconnection.RecordableHttpsURLConnection;
 import com.google.gson.JsonParseException;
 import org.junit.Assert;
 import org.junit.Test;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.io.OutputStream;
 import java.net.URISyntaxException;
 import java.nio.charset.StandardCharsets;
@@ -25,7 +27,7 @@
 
 import static com.easypost.easyvcr.internalutilities.Tools.readFromInputStream;
 
-public class HttpUrlConnectionTest {
+public class  HttpUrlConnectionTest {
 
     private static FakeDataService.IPAddressData getIPAddressDataRequest(Cassette cassette, Mode mode) throws Exception {
         RecordableHttpsURLConnection connection = TestUtils.getSimpleHttpsURLConnection(cassette.name, mode, null);
@@ -419,4 +421,32 @@ public void testExpirationSettings() throws Exception {
         Assert.assertThrows(RecordingExpirationException.class, () -> HttpClients.newClient(HttpClientType.HttpsUrlConnection,
                 FakeDataService.URL, cassette, Mode.Replay, finalAdvancedSettings));
     }
+
+    @Test
+    public void testReplayHttpError() throws Exception {
+        Cassette cassette = TestUtils.getCassette("test_replay_http_error");
+        cassette.erase(); // Erase cassette before recording
+
+        // make connection using Mode.Record
+        RecordableHttpsURLConnection connection =
+                (RecordableHttpsURLConnection) HttpClients.newClient(HttpClientType.HttpsUrlConnection,
+                        FakeDataService.URL, cassette, Mode.Record);
+        // make data service using connection
+        FakeDataService.HttpsUrlConnection fakeDataService = new FakeDataService.HttpsUrlConnection(connection);
+        // make HTTP call with data service (record to cassette)
+        RecordableHttpsURLConnection clientAfterRequest = fakeDataService.makeBadRequest();
+        Assert.assertTrue(cassette.numInteractions() > 0); // make sure we recorded something
+
+        // make connection using Mode.Replay
+        connection = (RecordableHttpsURLConnection) HttpClients.newClient(HttpClientType.HttpsUrlConnection,
+                FakeDataService.URL, cassette, Mode.Replay);
+        // make data service using connection
+        fakeDataService = new FakeDataService.HttpsUrlConnection(connection);
+        // make HTTP call with data service (replay from cassette)
+        clientAfterRequest = fakeDataService.makeBadRequest();
+
+        // make sure the error stream was loaded properly
+        Assert.assertNotNull(clientAfterRequest);
+        Assert.assertNotNull(clientAfterRequest.getErrorStream());
+    }
 }