How to make xcodebuild test recognize classes in the main app target

In my main target, I have a MyClass class. Then I try to access this class in my simple test case.

#import <UIKit/UIKit.h>
#import <XCTest/XCTest.h>
#import "MyClass.h"

@interface TryXcodeBotTests : XCTestCase

@end

@implementation TryXcodeBotTests

- (void)testExample {
    MyClass *object = [[MyClass alloc] init];

    // This is an example of a functional test case.
    XCTAssert(YES, @"Pass");
}

@end

In my test target, I already set the Host Application to my app, and check the Allow testing Host Application APIs. I go to Product > Test in my Xcode. The simulator shows up. The test went well. Great!

BUT!!! The problem is, when I try it with xcodebuild command line, it doesn't work.

This is the command.

/usr/bin/xcodebuild test -scheme TryXcodeBot \
-workspace TryXcodeBot.xcworkspace \
-configuration Release \
-destination 'platform=iOS Simulator,name=iPhone 5s'

This is the output, with errors at the end.

ld: warning: directory not found for option '-F/Applications/http://ift.tt/1QIfMIM'
Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_MyObject", referenced from:
      objc-class-ref in TryXcodeBotTests.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)


Testing failed:
    "_OBJC_CLASS_$_MyObject", referenced from:
    Linker command failed with exit code 1 (use -v to see invocation)
** TEST FAILED **


The following build commands failed:
    Ld /Users/thongchai/Library/Developer/Xcode/DerivedData/TryXcodeBot-ciwyldvaiganvlcceegjybtnqlto/Build/Intermediates/TryXcodeBot.build/Release-iphonesimulator/TryXcodeBotTests.build/Objects-normal/i386/TryXcodeBotTests normal i386
(1 failure)

I can't find a way to set the test Host Application when using xcodebuild to test. Or do anything to make the test recognize the class in my app file. I know I can manually add MyClass.h to my test target (which it works). But that's not what I want. I want MyClass to only exist in my main app target. Is there any way to do this?