angular unit test for throwing error fails

Question

Hi I wrote an angular unit test for a method which throws an error when there is no data. But that test is failing with the message TypeError: Cannot read property 'subscribe' of undefined. I tried so many things but still it fails.

This is the method in ts file

searchLogs(pageSize:number, pageIndex){
    let logs = this.logForm.value;
    logs.PageSize = pagesize;
    logs.PageIndex = pageIndex;
    
    this.myService.searchLogs(logs).subscribe((result)=> {
        let logResult = result;
        if(logResult){
            this.dataSource = new MatTableDataSource<LogElement>(logResult)}
        },
        
        err => {
            let errorMgs = err && err.error && err.error.error && err.error.error.message
            ? 'discription': '+ err.error.error.message.replace(/"/g, "").substring(0,250)
            : "Error occured!";
            });
}

this is the test case i wrote in spec.ts file

it('should run #searchLogs() with error', async() =>
{
    component.logForm = component.logForm || {};
    component.logForm.value = {
        PageSize: {},
        PageIndex: {}
    };
    component.myService = component.myService || {};
    const errorResponse = new HttpErrorResponse({
        error:{error: {error: "error", message: "Error occured!"}},
        status: 0,
        statusText: "Unknow Error",
    })
    
    const errorResponse1 = new HttpErrorResponse({
        error:{error: {error: "error", message: null}},
        status: 0,
        statusText: "Unknow Error",
    })
    mockMyService.searchLogs.and.returnValue(throwError(errorResponse));
    component.searchLogs({},{});
    expect(component.myService.searchLogs).toHaveBeenCalled();
    expect(component.dataSource.data).toEqual([]);
    
    mockMyService.searchLogs.and.returnValue(throwError(errorResponse1));
    component.searchLogs({},{});
    expect(component.myService.searchLogs).toHaveBeenCalled();
    expect(component.dataSource.data).toEqual([]);
}
);

Any idea why this is failing? Appreciate if anyone can help me :)

This is how i defined mockMyService

describe('LogViewerComponent', () => {
let mockMyService;

beforeEach(() => {
    mockMyService = jasmine.createSpyObj('MyService', ['searchLogs']);
    TestBed.configureTestingModule({
        imports:[FormsModule, ReactiveFormsModule],
        declarations:[LogViewerComponent],
        schemas:[CUSTOM_ELEMENTS_SCHEMA, NO_ERRORS_SCHEMA],
        providers: [
        {provide: MyService, useValue: mockMyService}
        ]
    }).overrideComponent(LogViewerComponent, {
        
    }). compileComponents();
    fixture = TestBed.createComponent(LogViewerComponent);
    component = fixture.debugElement.componentInstance;
});

afterEach(()=> {
component.ngOnDestroy = function(){};
fixture.destroy();
});

)};