public async Task PostTeacherTest()
{
//Arrange
TeachersController teachersController = new TeachersController(_inMemoryDBContext);
ActionResult <IEnumerable <Teacher> > _teacherList = await teachersController.GetTeachers();
int startingCount = _teacherList.Value.Count <Teacher>();
Teacher teacher = new Teacher();
teacher.TeacherName = "Señora Maestra";
//Act
ActionResult <Teacher> newTeacher = await teachersController.PostTeacher(teacher);
//Assert
CreatedAtActionResult postResult = (CreatedAtActionResult)newTeacher.Result;
Teacher createdTeacher = (Teacher)postResult.Value;
Assert.IsTrue(createdTeacher.TeacherKey > startingCount);
}