Use server URL from auth query if helper does not return one

core/src/main/java/org/testcontainers/utility/RegistryAuthLocator.java

@@ -318,13 +318,12 @@ private AuthConfig runCredentialProvider(String hostName, String helperOrStoreNa
 
         final String username = helperResponse.at("/Username").asText();
         final String password = helperResponse.at("/Secret").asText();
+        final String serverUrl = helperResponse.at("/ServerURL").asText();
+        final AuthConfig authConfig = new AuthConfig().withRegistryAddress(serverUrl.isEmpty() ? hostName : serverUrl);
         if ("<token>".equals(username)) {
-            return new AuthConfig().withIdentityToken(password);
+            return authConfig.withIdentityToken(password);
         } else {
-            return new AuthConfig()
-                .withRegistryAddress(helperResponse.at("/ServerURL").asText())
-                .withUsername(username)
-                .withPassword(password);
+            return authConfig.withUsername(username).withPassword(password);
         }
     }
 

core/src/test/java/org/testcontainers/utility/RegistryAuthLocatorTest.java

@@ -131,6 +131,9 @@ public void lookupAuthConfigUsingHelperWithToken() throws URISyntaxException, IO
             new AuthConfig()
         );
 
+        assertThat(authConfig.getRegistryAddress())
+            .as("Correct server URL is obtained from a credential store")
+            .isEqualTo("url");
         assertThat(authConfig.getIdentitytoken())
             .as("Correct identitytoken is obtained from a credential store")
             .isEqualTo("secret");
@@ -176,6 +179,45 @@ public void lookupNonEmptyAuthWithHelper() throws URISyntaxException, IOExceptio
             .isEqualTo("secret");
     }
 
+    @Test
+    public void lookupAuthConfigUsingHelperNoServerUrl() throws URISyntaxException, IOException {
+        final RegistryAuthLocator authLocator = createTestAuthLocator("config-with-helper-no-server-url.json");
+
+        final AuthConfig authConfig = authLocator.lookupAuthConfig(
+            DockerImageName.parse("registrynoserverurl.example.com/org/repo"),
+            new AuthConfig()
+        );
+
+        assertThat(authConfig.getRegistryAddress())
+            .as("Fallback (registry) server URL is used")
+            .isEqualTo("registrynoserverurl.example.com");
+        assertThat(authConfig.getUsername())
+            .as("Correct username is obtained from a credential store")
+            .isEqualTo("username");
+        assertThat(authConfig.getPassword())
+            .as("Correct secret is obtained from a credential store")
+            .isEqualTo("secret");
+    }
+
+    @Test
+    public void lookupAuthConfigUsingHelperNoServerUrlWithToken() throws URISyntaxException, IOException {
+        final RegistryAuthLocator authLocator = createTestAuthLocator(
+            "config-with-helper-no-server-url-using-token.json"
+        );
+
+        final AuthConfig authConfig = authLocator.lookupAuthConfig(
+            DockerImageName.parse("registrynoserverurltoken.example.com/org/repo"),
+            new AuthConfig()
+        );
+
+        assertThat(authConfig.getRegistryAddress())
+            .as("Fallback (registry) server URL is used")
+            .isEqualTo("registrynoserverurltoken.example.com");
+        assertThat(authConfig.getIdentitytoken())
+            .as("Correct identitytoken is obtained from a credential store")
+            .isEqualTo("secret");
+    }
+
     @Test
     public void lookupAuthConfigWithCredentialsNotFound() throws URISyntaxException, IOException {
         Map<String, String> notFoundMessagesReference = new HashMap<>();

core/src/test/resources/auth-config/config-with-helper-no-server-url-using-token.json

@@ -0,0 +1,11 @@
+{
+    "auths": {
+        "registrynoserverurltoken.example.com": {}
+    },
+    "HttpHeaders": {
+        "User-Agent": "Docker-Client/18.03.0-ce (darwin)"
+    },
+    "credHelpers": {
+        "registrynoserverurltoken.example.com": "fake"
+    }
+}

core/src/test/resources/auth-config/config-with-helper-no-server-url.json

@@ -0,0 +1,11 @@
+{
+    "auths": {
+        "registrynoserverurl.example.com": {}
+    },
+    "HttpHeaders": {
+        "User-Agent": "Docker-Client/18.03.0-ce (darwin)"
+    },
+    "credHelpers": {
+        "registrynoserverurl.example.com": "fake"
+    }
+}

core/src/test/resources/auth-config/docker-credential-fake

@@ -31,5 +31,19 @@ if [ "$inputLine" = "registrytoken.example.com" ]; then
         '}'
     exit 0
 fi
+if [ "$inputLine" = "registrynoserverurl.example.com" ]; then
+    echo '{' \
+        '  "Username": "username",' \
+        '  "Secret": "secret"' \
+        '}'
+    exit 0
+fi
+if [ "$inputLine" = "registrynoserverurltoken.example.com" ]; then
+    echo '{' \
+        '  "Username": "<token>",' \
+        '  "Secret": "secret"' \
+        '}'
+    exit 0
+fi
 
 exit 1