Stock trading system test requirements

Decision table

	Rule 1	Rule 2	Rule 3	Rule 4	Rule 5	Rule 6	Rule 7	Rule 8
Conditions
Valid symbol	No	No	No	No	Yes	Yes	Yes	Yes
Valid quantity	No	No	Yes	Yes	No	No	Yes	Yes
Enough money	No	Yes	No	Yes	No	Yes	No	Yes
Actions
Buy	No	No	No	No	No	No	No	Yes

However, if the symbol is invalid, the remaining conditions can be ignored. Thus, the decision table can be simplified:

	Rule 1	Rule 2	Rule 3	Rule 4	Rule 5
Conditions
Valid symbol	No	Yes	Yes	Yes	Yes
Valid quantity	N/A	No	No	Yes	Yes
Enough money	N/A	No	Yes	No	Yes
Actions
Buy	No	No	No	No	Yes

The rules 2 and 3 can also be simplified. The simpliest decision table is:

	Rule 1	Rule 2	Rule 3	Rule 4
Conditions
Valid symbol	No	Yes	Yes	Yes
Valid quantity	N/A	No	Yes	Yes
Enough money	N/A	N/A	No	Yes
Actions
Buy	No	No	No	Yes