Fixes #1113: Method signature corrected.
diff --git a/LibTest/io/HttpClient/addCredentials_A03_t01.dart b/LibTest/io/HttpClient/addCredentials_A03_t01.dart
index 4776dc9..08b2998 100644
--- a/LibTest/io/HttpClient/addCredentials_A03_t01.dart
+++ b/LibTest/io/HttpClient/addCredentials_A03_t01.dart
@@ -36,7 +36,7 @@
   });
 
   HttpClient client = new HttpClient();
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Digest", scheme);
     Expect.equals("server-realm", realm);
     Completer<bool> completer = new Completer<bool>();
diff --git a/LibTest/io/HttpClient/addProxyCredentials_A03_t01.dart b/LibTest/io/HttpClient/addProxyCredentials_A03_t01.dart
index bd3b29d..e5c2129 100644
--- a/LibTest/io/HttpClient/addProxyCredentials_A03_t01.dart
+++ b/LibTest/io/HttpClient/addProxyCredentials_A03_t01.dart
@@ -44,7 +44,7 @@
     return "PROXY ${localhost}:${server.port}";
   };
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Expect.equals(localhost, host);
     Expect.equals(server.port, port);
     Expect.equals("Digest", scheme);
diff --git a/LibTest/io/HttpClient/authenticateProxy_A01_t01.dart b/LibTest/io/HttpClient/authenticateProxy_A01_t01.dart
index 69f6332..e884a71 100644
--- a/LibTest/io/HttpClient/authenticateProxy_A01_t01.dart
+++ b/LibTest/io/HttpClient/authenticateProxy_A01_t01.dart
@@ -56,7 +56,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Expect.equals(InternetAddress.loopbackIPv4.address, host);
     Expect.equals(server.port, port);
     Expect.equals("Basic", scheme);
diff --git a/LibTest/io/HttpClient/authenticateProxy_A01_t02.dart b/LibTest/io/HttpClient/authenticateProxy_A01_t02.dart
index c51a931..43aa588 100644
--- a/LibTest/io/HttpClient/authenticateProxy_A01_t02.dart
+++ b/LibTest/io/HttpClient/authenticateProxy_A01_t02.dart
@@ -60,7 +60,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Expect.equals(InternetAddress.loopbackIPv4.address, host);
     Expect.equals(server.port, port);
     Expect.equals("Digest", scheme);
diff --git a/LibTest/io/HttpClient/authenticateProxy_A02_t01.dart b/LibTest/io/HttpClient/authenticateProxy_A02_t01.dart
index 4f2aa8d..356df5e 100644
--- a/LibTest/io/HttpClient/authenticateProxy_A02_t01.dart
+++ b/LibTest/io/HttpClient/authenticateProxy_A02_t01.dart
@@ -56,7 +56,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Expect.equals(InternetAddress.loopbackIPv4.address, host);
     Expect.equals(server.port, port);
     Expect.equals("Basic", scheme);
diff --git a/LibTest/io/HttpClient/authenticate_A01_t01.dart b/LibTest/io/HttpClient/authenticate_A01_t01.dart
index 3875da2..aa500b4 100644
--- a/LibTest/io/HttpClient/authenticate_A01_t01.dart
+++ b/LibTest/io/HttpClient/authenticate_A01_t01.dart
@@ -55,7 +55,7 @@
   });
   HttpClient client = new HttpClient();
 
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Digest", scheme);
     Expect.equals("realm", realm);
     Completer<bool> completer = new Completer<bool>();
diff --git a/LibTest/io/HttpClient/authenticate_A01_t02.dart b/LibTest/io/HttpClient/authenticate_A01_t02.dart
index c122c62..a12039e 100644
--- a/LibTest/io/HttpClient/authenticate_A01_t02.dart
+++ b/LibTest/io/HttpClient/authenticate_A01_t02.dart
@@ -48,7 +48,7 @@
   });
   HttpClient client = new HttpClient();
 
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Basic", scheme);
     Expect.equals("realm", realm);
     Completer<bool> completer = new Completer<bool>();
diff --git a/LibTest/io/HttpClient/authenticate_A02_t01.dart b/LibTest/io/HttpClient/authenticate_A02_t01.dart
index 985e87a..58ed587 100644
--- a/LibTest/io/HttpClient/authenticate_A02_t01.dart
+++ b/LibTest/io/HttpClient/authenticate_A02_t01.dart
@@ -49,7 +49,7 @@
   });
   HttpClient client = new HttpClient();
 
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Digest", scheme);
     Expect.equals("realm", realm);
     Completer<bool> completer = new Completer<bool>();
diff --git a/LibTest/io/HttpClient/findProxy_A01_t01.dart b/LibTest/io/HttpClient/findProxy_A01_t01.dart
index 278c8d6..873063d 100644
--- a/LibTest/io/HttpClient/findProxy_A01_t01.dart
+++ b/LibTest/io/HttpClient/findProxy_A01_t01.dart
@@ -66,7 +66,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
         authenticateProxyCalled = true;
         Completer<bool> completer = new Completer<bool>();
         completer.complete(true);
diff --git a/LibTest/io/HttpClient/findProxy_A01_t02.dart b/LibTest/io/HttpClient/findProxy_A01_t02.dart
index 0f2fd12..8fd1efc 100644
--- a/LibTest/io/HttpClient/findProxy_A01_t02.dart
+++ b/LibTest/io/HttpClient/findProxy_A01_t02.dart
@@ -66,7 +66,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
         authenticateProxyCalled = true;
         Completer<bool> completer = new Completer<bool>();
         completer.complete(true);
diff --git a/LibTest/io/HttpClient/findProxy_A02_t01.dart b/LibTest/io/HttpClient/findProxy_A02_t01.dart
index 55f0e6c..4c855d3 100644
--- a/LibTest/io/HttpClient/findProxy_A02_t01.dart
+++ b/LibTest/io/HttpClient/findProxy_A02_t01.dart
@@ -57,7 +57,7 @@
   HttpClient client = new HttpClient();
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Completer<bool> completer = new Completer<bool>();
     completer.complete(true);
     return completer.future;
diff --git a/LibTest/io/HttpClient/findProxy_A02_t02.dart b/LibTest/io/HttpClient/findProxy_A02_t02.dart
index dc2280b..3db45f8 100644
--- a/LibTest/io/HttpClient/findProxy_A02_t02.dart
+++ b/LibTest/io/HttpClient/findProxy_A02_t02.dart
@@ -57,7 +57,7 @@
   HttpClient client = new HttpClient();
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
     Completer<bool> completer = new Completer<bool>();
     completer.complete(true);
     return completer.future;
diff --git a/LibTest/io/HttpClient/findProxy_A03_t01.dart b/LibTest/io/HttpClient/findProxy_A03_t01.dart
index 4a93b74..8f2eda1 100644
--- a/LibTest/io/HttpClient/findProxy_A03_t01.dart
+++ b/LibTest/io/HttpClient/findProxy_A03_t01.dart
@@ -67,7 +67,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
         authenticateProxyCalled = true;
         Expect.equals(InternetAddress.loopbackIPv4.address, host);
         Expect.equals(server.port, port);
diff --git a/LibTest/io/HttpClient/findProxy_A03_t02.dart b/LibTest/io/HttpClient/findProxy_A03_t02.dart
index f31ece4..aff6752 100644
--- a/LibTest/io/HttpClient/findProxy_A03_t02.dart
+++ b/LibTest/io/HttpClient/findProxy_A03_t02.dart
@@ -72,7 +72,7 @@
   };
 
   client.authenticateProxy =
-      (String host, int port, String scheme, String realm) {
+      (String host, int port, String scheme, String? realm) {
         authenticateProxyCalled = true;
         Expect.equals(InternetAddress.loopbackIPv4.address, host);
         Expect.equals(server.port, port);
diff --git a/LibTest/io/HttpClientBasicCredentials/HttpClientBasicCredentials_A01_t01.dart b/LibTest/io/HttpClientBasicCredentials/HttpClientBasicCredentials_A01_t01.dart
index f372563..7c025bd 100644
--- a/LibTest/io/HttpClientBasicCredentials/HttpClientBasicCredentials_A01_t01.dart
+++ b/LibTest/io/HttpClientBasicCredentials/HttpClientBasicCredentials_A01_t01.dart
@@ -34,7 +34,7 @@
   });
   HttpClient client = new HttpClient();
 
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Basic", scheme);
     Expect.equals("realm", realm);
     Completer<bool> completer = new Completer<bool>();
diff --git a/LibTest/io/HttpClientDigestCredentials/HttpClientDigestCredentials_A01_t01.dart b/LibTest/io/HttpClientDigestCredentials/HttpClientDigestCredentials_A01_t01.dart
index 79f0756..e91a700 100644
--- a/LibTest/io/HttpClientDigestCredentials/HttpClientDigestCredentials_A01_t01.dart
+++ b/LibTest/io/HttpClientDigestCredentials/HttpClientDigestCredentials_A01_t01.dart
@@ -43,7 +43,7 @@
   });
   HttpClient client = new HttpClient();
 
-  client.authenticate = (Uri url, String scheme, String realm) {
+  client.authenticate = (Uri url, String scheme, String? realm) {
     Expect.equals("Digest", scheme);
     Expect.equals("realm", realm);
     Completer<bool> completer = new Completer<bool>();