added check for params

for AddTest, DeleteTest, ListTest, SearchTest, ShowTest, UpdateTest
replaced assertEquals(string, string) with compareTask where possible
Merge remote-tracking branch 'main/ImproveTests-command'

Conflicts:
	CEO/src/cs2103/command/AddTest.java
	CEO/src/cs2103/command/DeleteTest.java
	CEO/src/cs2103/command/ListTest.java
	CEO/src/cs2103/command/MarkTest.java
	CEO/src/cs2103/command/SearchTest.java
	CEO/src/cs2103/command/ShowTest.java
	CEO/src/cs2103/command/UpdateTest.java