System testing is basically a part of software testing and test plan should always contain specific space for this testing. To test the system as a whole, requirements and expectations should be clear and the tester needs to understand real time usage of application too.
The city of Milwaukee, Wisconsin was chosen as the location in which Happy Days was set. Tom Miller, one of the producers, grew up in Milwaukee. In addition, Milwaukee gave the show a midwest flavor that they thought would appeal to a broad-based audience.
Oh Happy Day was one of the first pop hits whose momentum was driven by the high-school teen set. Described as a garage hit, before the song was recorded, Don Howard Kaplow sang it accompanied by his guitar before his classmates at Cleveland Heights High School, in Cleveland, Ohio. At a Saturday high-school dance, the boys and girls called 13 times for Oh Happy Day.