From 545e2024b13c72b92ae7cd715f64de2619d7de69 Mon Sep 17 00:00:00 2001
From: whiskels <kuzmingeo@gmail.com>
Date: Fri, 12 Jul 2024 10:34:23 +0300
Subject: [PATCH] T-38: fixed NPE in comparator

---
 .../reporting/domain/HasBirthday.java         |  2 +-
 .../reporting/domain/HasBirthdayTest.java     | 62 +++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 src/test/java/com/whiskels/notifier/reporting/domain/HasBirthdayTest.java

diff --git a/src/main/java/com/whiskels/notifier/reporting/domain/HasBirthday.java b/src/main/java/com/whiskels/notifier/reporting/domain/HasBirthday.java
index 0c747bfe..c7b0c895 100644
--- a/src/main/java/com/whiskels/notifier/reporting/domain/HasBirthday.java
+++ b/src/main/java/com/whiskels/notifier/reporting/domain/HasBirthday.java
@@ -5,7 +5,7 @@
 
 public interface HasBirthday {
     static <T extends HasBirthday> Comparator<T> comparator() {
-        return Comparator.comparing(T::birthday).thenComparing(T::name);
+        return Comparator.comparing(T::birthday, Comparator.nullsLast(Comparator.naturalOrder())).thenComparing(T::name, Comparator.nullsLast(Comparator.naturalOrder()));
     }
 
 
diff --git a/src/test/java/com/whiskels/notifier/reporting/domain/HasBirthdayTest.java b/src/test/java/com/whiskels/notifier/reporting/domain/HasBirthdayTest.java
new file mode 100644
index 00000000..771c20a7
--- /dev/null
+++ b/src/test/java/com/whiskels/notifier/reporting/domain/HasBirthdayTest.java
@@ -0,0 +1,62 @@
+package com.whiskels.notifier.reporting.domain;
+
+import lombok.Builder;
+import org.junit.jupiter.api.Test;
+
+import java.time.LocalDate;
+import java.util.ArrayList;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class HasBirthdayTest {
+
+    @Test
+    void testComparator() {
+        var first = "FIRST";
+        var second = "SECOND";
+        var third = "THIRD";
+        var fourth = "FOURTH";
+
+        List<HasBirthday> input = new ArrayList<>();
+        input.add(
+                HasBirthdayImpl.builder()
+                        .name(fourth)
+                        .birthday(null)
+                        .build()
+        );
+        input.add(
+                HasBirthdayImpl.builder()
+                        .name(null)
+                        .birthday(null)
+                        .build()
+        );
+        input.add(
+                HasBirthdayImpl.builder()
+                        .name(first)
+                        .birthday(LocalDate.now())
+                        .build()
+        );
+        input.add(
+                HasBirthdayImpl.builder()
+                        .name(second)
+                        .birthday(LocalDate.now().plusDays(1))
+                        .build()
+        );
+        input.add(
+                HasBirthdayImpl.builder()
+                        .name(third)
+                        .birthday(LocalDate.now().plusDays(1))
+                        .build()
+        );
+
+        input.sort(HasBirthday.comparator());
+
+        assertThat(input).extracting(HasBirthday::name)
+                .containsExactly(first, second, third, fourth, null);
+    }
+
+    @Builder
+    record HasBirthdayImpl(String name, LocalDate birthday) implements HasBirthday {
+    }
+}
\ No newline at end of file