Add null check to MP Server.Builder.config() (#5363) (#5374)

* Add null check to MP Server.Builder.config()

* Improve the NullPointerException assertion test

config/config-mp/src/main/java/io/helidon/config/mp/MpConfigSources.java

@@ -352,7 +352,7 @@ public static ConfigSource create(io.helidon.config.spi.ConfigSource helidonConf
      * @return a new MicroProfile Config config source
      */
     public static ConfigSource create(Config config) {
-        return new MpHelidonConfigSource(config);
+        return new MpHelidonConfigSource(Objects.requireNonNull(config, "Config cannot be null"));
     }
 
     /**

config/config-mp/src/test/java/io/helidon/config/mp/MpConfigSourcesTest.java

@@ -24,6 +24,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import io.helidon.common.media.type.MediaType;
+import io.helidon.config.Config;
 import io.helidon.config.ConfigException;
 import io.helidon.config.ConfigSources;
 import io.helidon.config.PropertiesConfigParser;
@@ -37,6 +38,7 @@
 import io.helidon.config.spi.ParsableSource;
 
 import org.junit.jupiter.api.Test;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.CoreMatchers.nullValue;
@@ -100,6 +102,12 @@ void testHelidonLazy() {
         assertThat("exists called exactly once", lazy.exists.get(), is(1));
     }
 
+    @Test
+    void testMpConfigSourcesNullConfig() {
+        NullPointerException npe = assertThrows(NullPointerException.class, () -> MpConfigSources.create((Config) null));
+        assertThat(npe.getMessage(), is("Config cannot be null"));
+    }
+
     private static final class NodeImpl implements ConfigSource, NodeConfigSource {
         private static final String DESCRIPTION = "node-unit-test";
         private static final String KEY = "key";

microprofile/server/src/main/java/io/helidon/microprofile/server/Server.java

@@ -19,6 +19,7 @@
 import java.util.Arrays;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Objects;
 import java.util.logging.Logger;
 
 import io.helidon.common.context.Contexts;
@@ -292,7 +293,7 @@ public Builder port(int port) {
         public Builder config(io.helidon.config.Config config) {
             this.config = ConfigProviderResolver.instance()
                     .getBuilder()
-                    .withSources(MpConfigSources.create(config))
+                    .withSources(MpConfigSources.create(Objects.requireNonNull(config, "Config cannot be null")))
                     .build();
 
             return this;

microprofile/server/src/test/java/io/helidon/microprofile/server/ServerTest.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2019, 2022 Oracle and/or its affiliates.
+ *
+ * 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.helidon.microprofile.server;
+
+import io.helidon.config.Config;
+
+import org.junit.jupiter.api.Test;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+/**
+ * Unit test for {@link Server}.
+ */
+class ServerTest {
+
+    @Test
+    void testServerNullConfig() {
+        NullPointerException npe = assertThrows(NullPointerException.class, () -> Server.builder().config((Config) null).build());
+        assertThat(npe.getMessage(), is("Config cannot be null"));
+    }
+}