Polish BCrypt upgrade

Issue gh-7042

Author: rwinch

crypto/src/test/java/org/springframework/security/crypto/password/DelegatingPasswordEncoderTests.java

@@ -28,6 +28,7 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyZeroInteractions;
 import static org.mockito.Mockito.when;
@@ -215,8 +216,17 @@ public void upgradeEncodingWhenIdInvalidFormatThenTrue() {
 	}
 
 	@Test
-	public void upgradeEncodingWhenSameIdThenEncoderDecides() {
-		this.passwordEncoder.upgradeEncoding(this.bcryptEncodedPassword);
+	public void upgradeEncodingWhenSameIdAndEncoderFalseThenEncoderDecidesFalse() {
+		assertThat(this.passwordEncoder.upgradeEncoding(this.bcryptEncodedPassword)).isFalse();
+
+		verify(bcrypt).upgradeEncoding(this.encodedPassword);
+	}
+
+	@Test
+	public void upgradeEncodingWhenSameIdAndEncoderTrueThenEncoderDecidesTrue() {
+		when(this.bcrypt.upgradeEncoding(any())).thenReturn(true);
+
+		assertThat(this.passwordEncoder.upgradeEncoding(this.bcryptEncodedPassword)).isTrue();
 
 		verify(bcrypt).upgradeEncoding(this.encodedPassword);
 	}