Add unit test for populatePetTypes method in PetController

src/test/java/org/springframework/samples/petclinic/owner/PetControllerTest.java

@@ -0,0 +1,55 @@
+package org.springframework.samples.petclinic.owner;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.samples.petclinic.owner.PetController;
+import org.springframework.samples.petclinic.owner.OwnerRepository;
+import org.springframework.samples.petclinic.owner.PetType;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.verify;
+
+@ExtendWith(MockitoExtension.class)
+@DisplayName("PetController Tests")
+class PetControllerTest {
+
+	@Mock
+	private OwnerRepository ownerRepository;
+
+	@InjectMocks
+	private PetController petController;
+
+	@BeforeEach
+	void setup() {
+	}
+
+	@Test
+	@DisplayName("Test populatePetTypes")
+	void testPopulatePetTypes() {
+		PetType type1 = new PetType();
+		type1.setId(1);
+		type1.setName("Dog");
+
+		PetType type2 = new PetType();
+		type2.setId(2);
+		type2.setName("Cat");
+
+		doReturn(Arrays.asList(type1, type2)).when(ownerRepository).findPetTypes();
+
+		Collection<PetType> petTypes = petController.populatePetTypes();
+
+		assertThat(petTypes).hasSize(2);
+		assertThat(petTypes).contains(type1, type2);
+		verify(ownerRepository).findPetTypes();
+	}
+
+}