Understanding equivalence partitioning

It is impossible to test every possible input into your system, so we have to group them into categories demonstrating the behavior of a whole class of inputs. You are undoubtedly already doing that within your test plans, and its official name is equivalence partitioning. By considering it in the abstract, you can learn how to identify possible test cases quickly and completely.

For instance, to test whether a textbox can handle inputs including spaces, we could use the string “one two”. This string is an example of all possible strings that include a space between words. They are all equivalent, so we have partitioned them together, and that example is our single test to check the whole group. The following example strings test other partitions:

Partition	Example test
Strings including spaces	“...