Updated SimpleSavedRequest#getMethod

Before:
1. SimpleSavedRequest#getMethod returned null
2. SimpleSavedRequest(SavedRequest request) constructor did not set the method field from request

After:
1. SimpleSavedRequest#getMethod returns method property value
2. SimpleSavedRequest(SavedRequest request) constructor sets the method field from request

Closes gh-8675

Author: sentinalll

web/src/main/java/org/springframework/security/web/savedrequest/SimpleSavedRequest.java

@@ -57,6 +57,7 @@ public SimpleSavedRequest(SavedRequest request) {
 		}
 		this.locales = request.getLocales();
 		this.parameters = request.getParameterMap();
+		this.method = request.getMethod();
 	}
 
 	@Override
@@ -71,7 +72,7 @@ public List<Cookie> getCookies() {
 
 	@Override
 	public String getMethod() {
-		return null;
+		return this.method;
 	}
 
 	@Override

web/src/test/java/org/springframework/security/web/savedrequest/SimpleSavedRequestTests.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.security.web.savedrequest;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import javax.servlet.http.Cookie;
+import org.junit.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class SimpleSavedRequestTests {
+
+	@Test
+	public void constructorWhenGivenSavedRequestThenCopies() {
+		SavedRequest savedRequest = new SimpleSavedRequest(prepareSavedRequest());
+
+		assertThat(savedRequest.getMethod()).isEqualTo("POST");
+
+		List<Cookie> cookies = savedRequest.getCookies();
+		assertThat(cookies).hasSize(1);
+		Cookie cookie = cookies.get(0);
+		assertThat(cookie.getName()).isEqualTo("cookiename");
+		assertThat(cookie.getValue()).isEqualTo("cookievalue");
+
+		Collection<String> headerNames = savedRequest.getHeaderNames();
+		assertThat(headerNames).hasSize(1);
+		String headerName = headerNames.iterator().next();
+		assertThat(headerName).isEqualTo("headername");
+
+		List<String> headerValues = savedRequest.getHeaderValues("headername");
+		assertThat(headerValues).hasSize(1);
+		String headerValue = headerValues.get(0);
+		assertThat(headerValue).isEqualTo("headervalue");
+
+		List<Locale> locales = savedRequest.getLocales();
+		assertThat(locales).hasSize(1);
+		Locale locale = locales.get(0);
+		assertThat(locale).isEqualTo(Locale.ENGLISH);
+
+		Map<String, String[]> parameterMap = savedRequest.getParameterMap();
+		assertThat(parameterMap).hasSize(1);
+		String[] values = parameterMap.get("key");
+		assertThat(values).hasSize(1);
+		assertThat(values[0]).isEqualTo("value");
+	}
+
+	@Test
+	public void constructorWhenGivenRedirectUrlThenDefaultValues() {
+		SavedRequest savedRequest = new SimpleSavedRequest("redirectUrl");
+
+		assertThat(savedRequest.getMethod()).isEqualTo("GET");
+		assertThat(savedRequest.getCookies()).isEmpty();
+		assertThat(savedRequest.getHeaderNames()).isEmpty();
+		assertThat(savedRequest.getHeaderValues("headername")).isEmpty();
+		assertThat(savedRequest.getLocales()).isEmpty();
+		assertThat(savedRequest.getParameterMap()).isEmpty();
+	}
+
+	private SimpleSavedRequest prepareSavedRequest() {
+		SimpleSavedRequest	simpleSavedRequest = new SimpleSavedRequest("redirectUrl");
+		simpleSavedRequest.setCookies(Collections.singletonList(new Cookie("cookiename", "cookievalue")));
+		simpleSavedRequest.setMethod("POST");
+		simpleSavedRequest.setHeaders(Collections.singletonMap("headername", Collections.singletonList("headervalue")));
+		simpleSavedRequest.setLocales(Collections.singletonList(Locale.ENGLISH));
+		simpleSavedRequest.setParameters(Collections.singletonMap("key", new String[] {"value"}));
+		return simpleSavedRequest;
+	}
+
+}