From 7659a305087867d5b7256175cde20087ef0c0796 Mon Sep 17 00:00:00 2001
From: Michael Kwok <michael.kwok00@gmail.com>
Date: Mon, 22 Mar 2021 11:59:55 -0600
Subject: [PATCH 1/2] Add CityList::isEmpty, add corresponding test

---
 .../java/com/example/simpleparadox/listycity/CityList.java | 4 ++++
 .../com/example/simpleparadox/listycity/CityListTest.java  | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/app/src/main/java/com/example/simpleparadox/listycity/CityList.java b/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
index 6da242f3..17031f02 100644
--- a/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
+++ b/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
@@ -77,4 +77,8 @@ public void delete(City city) {
     public int countCities() {
         return cities.size();
     }
+
+    public boolean isEmpty() {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java b/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
index 787eab7e..7da65e56 100644
--- a/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
+++ b/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
@@ -93,4 +93,11 @@ void testCountCities() {
 
         assertEquals(1, cityList.countCities());
     }
+
+    @Test
+    void testListIsEmpty() {
+        CityList cityList = mockCityList();
+
+        assertFalse(cityList.isEmpty());
+    }
 }
\ No newline at end of file

From 5813ee592e4abafb613f82b7a3ebc4f56f5b08b3 Mon Sep 17 00:00:00 2001
From: Michael Kwok <michael.kwok00@gmail.com>
Date: Mon, 22 Mar 2021 12:07:24 -0600
Subject: [PATCH 2/2] Implement CityList::isEmpty, passing tests.

---
 .../main/java/com/example/simpleparadox/listycity/CityList.java | 2 +-
 .../java/com/example/simpleparadox/listycity/CityListTest.java  | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/com/example/simpleparadox/listycity/CityList.java b/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
index 17031f02..af053650 100644
--- a/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
+++ b/app/src/main/java/com/example/simpleparadox/listycity/CityList.java
@@ -79,6 +79,6 @@ public int countCities() {
     }
 
     public boolean isEmpty() {
-        throw new UnsupportedOperationException();
+        return cities.isEmpty();
     }
 }
diff --git a/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java b/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
index 7da65e56..5831b5c7 100644
--- a/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
+++ b/app/src/test/java/com/example/simpleparadox/listycity/CityListTest.java
@@ -99,5 +99,7 @@ void testListIsEmpty() {
         CityList cityList = mockCityList();
 
         assertFalse(cityList.isEmpty());
+        cityList.delete(mockCity());
+        assertTrue(cityList.isEmpty());
     }
 }
\ No newline at end of file