From 071e5dc6b2ba2b03dcee4a85d7768eda6337e543 Mon Sep 17 00:00:00 2001
From: Sjaak Derksen <sjaakd@users.noreply.github.com>
Date: Sun, 10 Nov 2019 20:14:33 +0100
Subject: [PATCH] #1966 extra unit test (#1967)

---
 .../ap/test/bugs/_1966/Issue1966Mapper.java   | 55 +++++++++++++++++++
 .../ap/test/bugs/_1966/Issue1966Test.java     | 36 ++++++++++++
 2 files changed, 91 insertions(+)
 create mode 100644 processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Mapper.java
 create mode 100644 processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Test.java

diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Mapper.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Mapper.java
new file mode 100644
index 000000000..13f4d489b
--- /dev/null
+++ b/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Mapper.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1966;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.NullValueCheckStrategy;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Sjaak Derksen
+ */
+@Mapper( imports = Collections.class )
+public interface Issue1966Mapper {
+
+    Issue1966Mapper INSTANCE = Mappers.getMapper( Issue1966Mapper.class );
+
+    @Mapping(target = "previousNames",
+        nullValueCheckStrategy = NullValueCheckStrategy.ALWAYS,
+        defaultExpression = "java(Collections.emptyList())")
+    Animal toAnimal(AnimalRecord record);
+
+    class AnimalRecord {
+
+         private String[] previousNames;
+
+        public String[] getPreviousNames() {
+            return previousNames;
+        }
+
+        public void setPreviousNames(String[] previousNames) {
+            this.previousNames = previousNames;
+        }
+    }
+
+    class Animal {
+
+        private List<String> previousNames;
+
+        public List<String> getPreviousNames() {
+            return previousNames;
+        }
+
+        public void setPreviousNames(List<String> previousNames) {
+            this.previousNames = previousNames;
+        }
+    }
+
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Test.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Test.java
new file mode 100644
index 000000000..9ad37958d
--- /dev/null
+++ b/processor/src/test/java/org/mapstruct/ap/test/bugs/_1966/Issue1966Test.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._1966;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.runner.AnnotationProcessorTestRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Sjaak Derksen
+ */
+@IssueKey("1966")
+@RunWith(AnnotationProcessorTestRunner.class)
+@WithClasses({
+    Issue1966Mapper.class
+})
+public class Issue1966Test {
+
+    @Test
+    public void shouldSelectDefaultExpressionEvenWhenSourceInMappingIsNotSpecified() {
+
+        Issue1966Mapper.AnimalRecord dto = new Issue1966Mapper.AnimalRecord();
+
+        Issue1966Mapper.Animal entity = Issue1966Mapper.INSTANCE.toAnimal( dto );
+
+        assertThat( entity.getPreviousNames() ).isNotNull();
+        assertThat( entity.getPreviousNames() ).isEmpty();
+    }
+}