Fix App Engine tests for Windows.

This change addresses several issues that prevented App Engine tests from passing on Windows:

- **Maven Wrapper:** The Maven wrapper executable `mvnw` is now invoked with the `.cmd` extension when running on Windows to ensure it can be executed correctly.
- **Newline Handling:** Test output reading logic has been updated to handle both `\n` and `\r\n` newline representations, which is necessary for Windows compatibility.

These changes ensure that the affected tests pass on both Linux/macOS and Windows environments.

PiperOrigin-RevId: 736207509
Change-Id: I7c11b010689343ccdbf9b29801e17569064bb867

Author: ludoch

e2etests/stagingtests/src/test/java/com/google/appengine/tools/admin/ApplicationTest.java

@@ -141,7 +141,9 @@ public class ApplicationTest {
       getWarPath("stage-with-appid-and-version");
   private static final String STAGE_WITH_STAGING_OPTIONS = getWarPath("stage-with-staging-options");
 
-  private static final int RANDOM_HTML_SIZE = 704;
+  // Size is different on Windows because of the extra \r\n characters in the HTML.
+  private static final int RANDOM_HTML_SIZE =
+      ((System.getProperty("os.name").toLowerCase().contains("windows")) ? 727 : 704);
   private static final String APPID = "sampleapp";
   private static final String MODULE_ID = "stan";
   private static final String APPVER = "1";

lib/tools_api/src/test/java/com/google/appengine/tools/admin/AppYamlTranslatorTest.java

@@ -2775,8 +2775,9 @@ public void testHttpHeaders() {
             + "  login: optional\n"
             + "  secure: optional\n"
             + "  http_headers:\n"
-            + "    foo: 1\n"
-            + "    bar: barf\n"
+            // Yaml library emitting headers is OS dependent so eol is different on Windows.
+            + "    foo: 1" +  System.getProperty("line.separator")
+            + "    bar: barf" +  System.getProperty("line.separator")
             + "- url: /\n"
             + "  script: unused\n"
             + "  login: optional\n"
@@ -2790,7 +2791,7 @@ public void testHttpHeaders() {
             + "  login: optional\n"
             + "  secure: optional\n";
     assertEquals(yaml, translator.getYaml());
-    
+
   }
 
   public void testBackends() {

runtime/impl/src/test/java/com/google/apphosting/runtime/ClassPathUtilsTest.java

@@ -64,8 +64,8 @@ public void verifyJava11PropertiesAreConfigured() throws Exception {
     }
     assertThat(System.getProperty("classpath.connector-j")).isNull();
 
-    assertThat(cpu.getFrozenApiJar().getAbsolutePath())
-        .isEqualTo(runtimeLocation + "/appengine-api-1.0-sdk.jar");
+    assertThat(cpu.getFrozenApiJar().getCanonicalPath())
+        .isEqualTo(new File(runtimeLocation + "/appengine-api-1.0-sdk.jar").getCanonicalPath());
   }
 
   @Test

runtime/test/src/test/java/com/google/apphosting/runtime/jetty9/GzipHandlerTest.java

@@ -117,9 +117,16 @@ public void testRequestGzipContent() throws Exception {
     Result response = completionListener.get(5, TimeUnit.SECONDS);
     assertThat(response.getResponse().getStatus(), equalTo(HttpStatus.OK_200));
     String contentReceived = received.toString();
-    assertThat(contentReceived, containsString("\nX-Content-Encoding: gzip\n"));
-    assertThat(contentReceived, not(containsString("\nContent-Encoding: gzip\n")));
-    assertThat(contentReceived, containsString("\nAccept-Encoding: gzip\n"));
+    if (!System.getProperty("os.name").toLowerCase().contains("windows")) {
+      // Linux
+      assertThat(contentReceived, containsString("\nX-Content-Encoding: gzip\n"));
+      assertThat(contentReceived, not(containsString("\nContent-Encoding: gzip\n")));
+      assertThat(contentReceived, containsString("\nAccept-Encoding: gzip\n"));
+    } else { // Windows
+      assertThat(contentReceived, containsString("\r\nX-Content-Encoding: gzip\r\n"));
+      assertThat(contentReceived, not(containsString("\r\nContent-Encoding: gzip\r\n")));
+      assertThat(contentReceived, containsString("\r\nAccept-Encoding: gzip\r\n"));
+    }
 
     // Server correctly echoed content of request.
     String expectedData = new String(data);

runtime/test/src/test/java/com/google/apphosting/runtime/jetty9/SpringBootTest.java

@@ -39,7 +39,10 @@ public static void beforeClass() throws IOException, InterruptedException {
     File currentDirectory = new File("").getAbsoluteFile();
     Process process =
         new ProcessBuilder(
-                "../../mvnw",
+                "../../mvnw"
+                    + ((System.getProperty("os.name").toLowerCase().contains("windows"))
+                        ? ".cmd" // Windows OS
+                        : ""), // Linux OS, no extension for command name.
                 "install",
                 "appengine:stage",
                 "-f",