fix(breadcrumb): Fix possible NPE in init without metadata (#585)

CHANGELOG.md

@@ -19,6 +19,9 @@
   [#513](https://github.com/bugsnag/bugsnag-android/pull/513)
 * Prevent overwrite of signal mask when installing ANR handler
   [#520](https://github.com/bugsnag/bugsnag-android/pull/520)
+* Fix possible null pointer exception when creating a breadcrumb without
+  metadata
+  [#585](https://github.com/bugsnag/bugsnag-android/pull/585)
 
 ## 4.21.1 (2019-10-15)
 

bugsnag-android-core/src/main/java/com/bugsnag/android/Breadcrumb.java

@@ -48,6 +48,12 @@ public final class Breadcrumb implements JsonStream.Streamable {
                @NonNull BreadcrumbType type,
                @NonNull Date captureDate,
                @NonNull Map<String, String> metadata) {
+        if (captureDate == null) {
+            captureDate = new Date();
+        }
+        if (metadata == null) {
+            metadata = new HashMap<>();
+        }
         this.timestamp = DateUtils.toIso8601(captureDate);
         this.type = type;
         this.name = name;

sdk/src/androidTest/java/com/bugsnag/android/BreadcrumbNullabilityTest.java

@@ -0,0 +1,31 @@
+package com.bugsnag.android;
+
+import static org.junit.Assert.assertEquals;
+
+import android.support.test.filters.SmallTest;
+import android.support.test.runner.AndroidJUnit4;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import java.util.Date;
+
+@RunWith(AndroidJUnit4.class)
+@SmallTest
+public class BreadcrumbNullabilityTest {
+
+    @Test
+    public void testCreateBreadcrumbWithoutMetadata() {
+        Breadcrumb crumb = new Breadcrumb("badger spotted", BreadcrumbType.USER, null);
+        assertEquals("badger spotted", crumb.getName());
+        assertEquals(BreadcrumbType.USER, crumb.getType());
+        assertEquals(0, crumb.getMetadata().size());
+    }
+
+    @Test
+    public void testCreateFullBreadcrumbWithoutMetadata() {
+        Breadcrumb crumb = new Breadcrumb("badger spotted", BreadcrumbType.USER, new Date(), null);
+        assertEquals("badger spotted", crumb.getName());
+        assertEquals(BreadcrumbType.USER, crumb.getType());
+        assertEquals(0, crumb.getMetadata().size());
+    }
+}