Add behavioral tests for ObjectMapper.registerModule(Module) (#3873)

src/test/java/com/fasterxml/jackson/databind/ModuleRegistrationTest.java

@@ -0,0 +1,86 @@
+package com.fasterxml.jackson.databind;
+
+import com.fasterxml.jackson.core.Version;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+
+public class ModuleRegistrationTest extends BaseMapTest {
+
+    public void testCopyHasSameRegisteredModulesInDifferentSetInstances() {
+        ObjectMapper originalMapper = newJsonMapper();
+        originalMapper.registerModule(_testModuleWithId("first"));
+        originalMapper.registerModule(_testModuleWithId("second"));
+
+        ObjectMapper copyMapper = originalMapper.copy();
+
+        assertNotSame(originalMapper, copyMapper);
+        assertNotSame(originalMapper._registeredModuleTypes, copyMapper._registeredModuleTypes);
+        assertEquals(originalMapper.getRegisteredModuleIds(), copyMapper.getRegisteredModuleIds());
+        assertTrue(originalMapper._registeredModuleTypes.containsAll(copyMapper._registeredModuleTypes));
+    }
+
+    private SimpleModule _testModuleWithId(String id) {
+        return new SimpleModule() {
+            @Override
+            public Object getTypeId() {
+                return id;
+            }
+        };
+    }
+
+    public void testRegisterNullModuleFails() {
+        ObjectMapper objectMapper = newJsonMapper();
+        try {
+            objectMapper.registerModule(null);
+            fail("should not pass");
+        } catch (IllegalArgumentException e) {
+            verifyException(e, "argument \"module\" is null");
+        }
+    }
+
+    public void testRegisterModuleWithNullNameFails() {
+        ObjectMapper objectMapper = newJsonMapper();
+        try {
+            objectMapper.registerModule(new Module() {
+                @Override
+                public String getModuleName() {
+                    return null;
+                }
+
+                @Override
+                public Version version() {
+                    return Version.unknownVersion();
+                }
+
+                @Override
+                public void setupModule(SetupContext context) {}
+            });
+            fail("should not pass");
+        } catch (IllegalArgumentException e) {
+            verifyException(e, "Module without defined name");
+        }
+    }
+
+    public void testRegisterModuleWithNullVersionFails() {
+        ObjectMapper objectMapper = newJsonMapper();
+        try {
+            objectMapper.registerModule(new Module() {
+                @Override
+                public String getModuleName() {
+                    return "some-module-name";
+                }
+
+                @Override
+                public Version version() {
+                    return null;
+                }
+
+                @Override
+                public void setupModule(SetupContext context) {}
+            });
+            fail("should not pass");
+        } catch (IllegalArgumentException e) {
+            verifyException(e, "Module without defined version");
+        }
+    }
+
+}