Add tests to try to reproduce databind/2852 (but won't fail)

Author: cowtowncoder

parameter-names/src/test/java/com/fasterxml/jackson/module/paramnames/ConstructorDetectorConfigTest.java

@@ -0,0 +1,53 @@
+package com.fasterxml.jackson.module.paramnames;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.cfg.ConstructorDetector;
+
+public class ConstructorDetectorConfigTest
+    extends ModuleTestBase
+{
+    static class SingleArgImmutable {
+        final String v;
+
+        public SingleArgImmutable(String value) { v = value; }
+    }
+    
+    private final ObjectMapper MAPPER = newMapper();
+
+    @Test
+    public void testSimpleImmutable() throws Exception
+    {
+        ImmutableBean input = new ImmutableBean("value", 42);
+        final String json = MAPPER.writeValueAsString(input);
+        ImmutableBean result = MAPPER.readValue(json, ImmutableBean.class);
+        assertEquals(input, result);
+    }
+
+    // [databind#2852]
+    @Test
+    public void testSimpleArgNonAnnotatedProperties() throws Exception
+    {
+        final ObjectMapper mapper = mapperBuilder()
+                .constructorDetector(ConstructorDetector.USE_PROPERTIES_BASED)
+                .build();
+        SingleArgImmutable result = mapper.readValue("{\"value\": \"foo\"}",
+                SingleArgImmutable.class);
+        assertEquals("foo", result.v);
+    }
+
+    // [databind#2852]
+    @Test
+    public void testSimpleArgNonAnnotatedDelegating() throws Exception
+    {
+        final ObjectMapper mapper = mapperBuilder()
+                .constructorDetector(ConstructorDetector.USE_DELEGATING)
+                .build();
+        SingleArgImmutable result = mapper.readValue("\"bar\"",
+                SingleArgImmutable.class);
+        assertEquals("bar", result.v);
+    }
+}

parameter-names/src/test/java/com/fasterxml/jackson/module/paramnames/ImmutableBean.java

@@ -1,69 +1,47 @@
 package com.fasterxml.jackson.module.paramnames;
 
-import com.fasterxml.jackson.annotation.JsonCreator;
-
 /**
  * @author Lovro Pandzic
  */
-class ImmutableBean {
-
+class ImmutableBean
+{
     private final String name;
     private final Integer value;
 
     // needed because names are implicit (as of Jackson 2.4), not explicit
-    @JsonCreator
+    // 14-Oct-2020, tatu: As of 2.12, no longer needed (was fixed earlier)
+//    @JsonCreator
     public ImmutableBean(String name, Integer value) {
-
         this.name = name;
         this.value = value;
     }
 
     public String getName() {
-
         return name;
     }
 
     public Integer getValue() {
-
         return value;
     }
 
     @Override
     public int hashCode() {
-
-        int result = name != null ? name.hashCode() : 0;
-        result = 31 * result + (value != null ? value.hashCode() : 0);
-        return result;
+        return name.hashCode() + value.hashCode();
     }
 
     @Override
     public boolean equals(Object o) {
-
-        if (this == o) {
-            return true;
-        }
+        if (this == o) return true;
         if (o == null || getClass() != o.getClass()) {
             return false;
         }
 
         final ImmutableBean that = (ImmutableBean) o;
-
-        if (name != null ? !name.equals(that.name) : that.name != null) {
-            return false;
-        }
-        if (value != null ? !value.equals(that.value) : that.value != null) {
-            return false;
-        }
-
-        return true;
+        return name.equals(that.name) && value.equals(that.value);
     }
 
     @Override
     public String toString() {
-
-        return "ImmutableBean{" +
-                "name='" + name + '\'' +
-                ", value=" + value +
-                '}';
+        return "ImmutableBean{name='" + name + "', value=" + value +'}';
     }
 }

parameter-names/src/test/java/com/fasterxml/jackson/module/paramnames/ModuleTestBase.java

@@ -3,6 +3,7 @@
 import java.util.Arrays;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 
 public class ModuleTestBase
 {
@@ -11,6 +12,11 @@ protected static ObjectMapper newMapper() {
                 .registerModule(new ParameterNamesModule());
     }
 
+    protected static JsonMapper.Builder mapperBuilder() {
+        return JsonMapper.builder()
+                .addModule(new ParameterNamesModule());
+    }
+
     protected String quote(String value) {
         return "\"" + value + "\"";
     }