1 files changed, 35 insertions, 6 deletions
diff --git a/src/objective-c/tests/GRPCClientTests.m b/src/objective-c/tests/GRPCClientTests.m
index 82ac2600fa..5672bdad4c 100644
--- a/src/objective-c/tests/GRPCClientTests.m
+++ b/src/objective-c/tests/GRPCClientTests.m
@@ -18,6 +18,7 @@
 
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
+#import <grpc/grpc.h>
 
 #import <GRPCClient/GRPCCall.h>
 #import <GRPCClient/GRPCCall+ChannelArg.h>
@@ -30,6 +31,8 @@
 #import <RxLibrary/GRXWriter+Immediate.h>
 #import <RxLibrary/GRXBufferedPipe.h>
 
+#import "version.h"
+
 #define TEST_TIMEOUT 16
 
 static NSString * const kHostAddress = @"localhost:5050";
@@ -266,12 +269,38 @@ static GRPCProtoMethod *kFullDuplexCallMethod;
   id<GRXWriteable> responsesWriteable = [[GRXWriteable alloc] initWithValueHandler:^(NSData *value) {
     XCTAssertNotNil(value, @"nil value received as response.");
     XCTAssertEqual([value length], 0, @"Non-empty response received: %@", value);
-    /* This test needs to be more clever in regards to changing the version of the core.
-    XCTAssertEqualObjects(call.responseHeaders[@"x-grpc-test-echo-useragent"],
-                          @"Foo grpc-objc/0.13.0 grpc-c/0.14.0-dev (ios)",
-                          @"Did not receive expected user agent %@",
-                          call.responseHeaders[@"x-grpc-test-echo-useragent"]);
-    */
+
+    NSString *userAgent = call.responseHeaders[@"x-grpc-test-echo-useragent"];
+    NSError *error = nil;
+
+    // Test the regex is correct
+    NSString *expectedUserAgent = @"Foo grpc-objc/";
+    expectedUserAgent =
+        [expectedUserAgent stringByAppendingString:GRPC_OBJC_VERSION_STRING];
+    expectedUserAgent =
+        [expectedUserAgent stringByAppendingString:@" grpc-c/"];
+    expectedUserAgent =
+        [expectedUserAgent stringByAppendingString:GRPC_C_VERSION_STRING];
+    expectedUserAgent =
+        [expectedUserAgent stringByAppendingString:@" (ios; chttp2; "];
+    expectedUserAgent =
+        [expectedUserAgent stringByAppendingString:[NSString stringWithUTF8String:grpc_g_stands_for()]];
+    expectedUserAgent = [expectedUserAgent stringByAppendingString:@")"];
+    XCTAssertEqualObjects(userAgent, expectedUserAgent);
+
+    // Change in format of user-agent field in a direction that does not match the regex will likely
+    // cause problem for certain gRPC users. For details, refer to internal doc https://goo.gl/c2diBc
+    NSRegularExpression *regex =
+        [NSRegularExpression regularExpressionWithPattern:@" grpc-[a-zA-Z0-9]+(-[a-zA-Z0-9]+)?/[^ ,]+( \\([^)]*\\))?"
+                                                  options:0
+                                                    error:&error];
+    NSString *customUserAgent =
+        [regex stringByReplacingMatchesInString:userAgent
+                                        options:0
+                                          range:NSMakeRange(0, [userAgent length])
+                                   withTemplate:@""];
+    XCTAssertEqualObjects(customUserAgent, @"Foo");
+
     [response fulfill];
   } completionHandler:^(NSError *errorOrNil) {
     XCTAssertNil(errorOrNil, @"Finished with unexpected error: %@", errorOrNil);