Requests without an Accept header are not accepted

Closes smallrye#497

implementation/src/main/java/io/smallrye/metrics/MetricsRequestHandler.java

@@ -272,6 +272,10 @@ Optional<String> getBestMatchingMediaType(Stream<String> acceptHeaders) {
             }
         });
 
+        if (tupleList.isEmpty()) {
+            return Optional.of(TEXT_PLAIN);
+        }
+
         WTTuple bestMatchTuple = new WTTuple(-1, null);
 
         // Iterate over the list and find the best match

implementation/src/test/java/io/smallrye/metrics/MediaHandlerTest.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2018 Red Hat, Inc. and/or its affiliates
+ * and other contributors as indicated by the @author tags.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.smallrye.metrics;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Optional;
+import java.util.stream.Stream;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * @author hrupp
+ */
+public class MediaHandlerTest {
+
+    MetricsRequestHandler requestHandler;
+
+    @Before
+    public void setUp() {
+
+        requestHandler = new MetricsRequestHandler();
+    }
+
+    @Test
+    public void testNotSamePrio() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.1",
+                "text/plain;q=0.9"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testNotSamePrio2() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.1,text/plain;q=0.9"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testSamePrio() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.5",
+                "text/plain;q=0.5"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testSamePrio2() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("text/plain;q=0.5",
+                "application/json;q=0.5"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testNoMatch() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("image/png",
+                "image/jpeg "));
+        assertThat(res.isPresent()).isFalse();
+    }
+
+    @Test
+    public void testBoth() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.1",
+                "text/plain;q=0.9"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo(("text/plain"));
+    }
+
+    @Test
+    public void testBoth2() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.1,text/plain;q=0.9"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo(("text/plain"));
+    }
+
+    @Test
+    public void testBoth3() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.8",
+                "text/plain;q=0.1"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("application/json");
+    }
+
+    @Test
+    public void testBoth4() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;q=0.8",
+                "text/plain;q=0.5",
+                "*/*;q=0.1"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("application/json");
+    }
+
+    @Test
+    public void testStarStarOnly() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("*/*"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testStarMix() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("*/*;q=0.1",
+                "image/png;q=1"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testStarMix2() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("image/png;q=1",
+                "*/*;q=0.1"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+    @Test
+    public void testWithMissingPrioritySingle() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("application/json;charset=UTF-8"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("application/json");
+    }
+
+    @Test
+    public void testWithMissingPriorityMulti() {
+        // default q=1 so json should be preferred
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.of("text/plain;q=0.8;charset=UTF-8",
+                "application/json;charset=UTF-8"));
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("application/json");
+    }
+
+    @Test
+    public void testDefaultMediaTypeWhenAcceptHeaderNotSet() {
+        Optional<String> res = requestHandler.getBestMatchingMediaType(Stream.empty());
+        assertThat(res.isPresent()).isTrue();
+        assertThat(res.get()).isEqualTo("text/plain");
+    }
+
+}