public void Exists_WithNotExistingName_ShouldReturnFalse()
{
// Arrange
StarStuffDbContext db = this.Database;
PlanetService planetService = new PlanetService(db);
string name = this.GetFakePlanets().First().Name;
// Act
bool result = planetService.Exists(name);
// Assert
Assert.False(result);
}