The point is that you can use real data with your own isolated test bed.
I'm not going to involve some random thing on the Internet in my test setup!
For one thing, I'm pretty sure I'd be violating a document that I signed about promising to safeguard my client's IT security, secrets and intellectual property.
Real data could be sensitive.
Anything of this sort that you set up will eventually be used by other people, who don't always know the full ramifications of what they are using. Somewhere down the line, someone will leak something into the test system. Maybe a user ID or password. Names of clients. Whatever.
Also, a test system has to be reliably operational. According to Murphy's Law, someone's thing you depend on on the Internet gonna disappear exactly when a lot of integration activity starts happening before a release.
Lastly, you should control every aspect of a test tool. Exactly how someone's SMTP thing handles SMTP could change in subtle ways from one day to the next.
I'm not going to involve some random thing on the Internet in my test setup!
For one thing, I'm pretty sure I'd be violating a document that I signed about promising to safeguard my client's IT security, secrets and intellectual property.
Real data could be sensitive.
Anything of this sort that you set up will eventually be used by other people, who don't always know the full ramifications of what they are using. Somewhere down the line, someone will leak something into the test system. Maybe a user ID or password. Names of clients. Whatever.
Also, a test system has to be reliably operational. According to Murphy's Law, someone's thing you depend on on the Internet gonna disappear exactly when a lot of integration activity starts happening before a release.
Lastly, you should control every aspect of a test tool. Exactly how someone's SMTP thing handles SMTP could change in subtle ways from one day to the next.