Handle relative instance URIs

Author: acoburn

solid/src/main/java/com/inrupt/client/solid/SolidProblemDetails.java

@@ -154,9 +154,10 @@ static SolidProblemDetails fromErrorResponse(final URI uri, final int statusCode
                 final URI type = Optional.ofNullable(pdData.type)
                     .map(uri::resolve)
                     .orElse(ProblemDetails.DEFAULT_TYPE);
+                final URI instance = pdData.instance != null ? uri.resolve(pdData.instance) : null;
                 // JSON mappers map invalid integers to 0, which is an invalid value in our case anyway.
                 final int status = Optional.of(pdData.status).filter(s -> s != 0).orElse(statusCode);
-                return new SolidProblemDetails(type, pdData.title, pdData.detail, status, pdData.instance);
+                return new SolidProblemDetails(type, pdData.title, pdData.detail, status, instance);
             } catch (IOException e) {
                 LOGGER.debug("Unable to parse ProblemDetails response from server", e);
             }

solid/src/test/java/com/inrupt/client/solid/SolidProblemDetailsTest.java

@@ -31,6 +31,7 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
@@ -67,6 +68,7 @@ void testEmptyProblemDetails() {
     @Test
     void testRelativeUriProblemDetails() {
         final int statusCode = 400;
+        final UUID instance = UUID.randomUUID();
         final ProblemDetails pd = SolidProblemDetails.fromErrorResponse(
                 POD,
                 statusCode,
@@ -75,21 +77,21 @@ void testRelativeUriProblemDetails() {
                     "\"title\":\"Some title\"," +
                     "\"status\":400," +
                     "\"detail\":\"Some details\"," +
-                    "\"instance\":\"https://example.org/instance\"," +
+                    "\"instance\":\"Instance" + instance + "\"," +
                     "\"type\":\"SomeType\"" +
                 "}").getBytes()
         );
         assertEquals(URI.create("https://storage.test/pod/SomeType"), pd.getType());
         assertEquals(statusCode, pd.getStatus());
         Assertions.assertEquals("Some title", pd.getTitle());
         assertEquals("Some details", pd.getDetail());
-        assertEquals("https://example.org/instance", pd.getInstance().toString());
+        assertEquals("https://storage.test/pod/Instance" + instance, pd.getInstance().toString());
     }
 
-
     @Test
     void testCompleteProblemDetails() {
         final int statusCode = 400;
+        final UUID instance = UUID.randomUUID();
         final ProblemDetails pd = SolidProblemDetails.fromErrorResponse(
                 POD,
                 statusCode,
@@ -98,15 +100,15 @@ void testCompleteProblemDetails() {
                     "\"title\":\"Some title\"," +
                     "\"status\":400," +
                     "\"detail\":\"Some details\"," +
-                    "\"instance\":\"https://example.org/instance\"," +
+                    "\"instance\":\"urn:uuid:" + instance + "\"," +
                     "\"type\":\"https://example.org/type\"" +
                 "}").getBytes()
         );
         assertEquals("https://example.org/type", pd.getType().toString());
         assertEquals(statusCode, pd.getStatus());
         Assertions.assertEquals("Some title", pd.getTitle());
         assertEquals("Some details", pd.getDetail());
-        assertEquals("https://example.org/instance", pd.getInstance().toString());
+        assertEquals("urn:uuid:" + instance, pd.getInstance().toString());
     }
 
     @Test