Need to design query or MS SQL procedure

Lets say I have 2 tables

Student_table:

studentID, lname, fname

Test_table:

testid, studentid, testname, testdate

There are 2 tests student can take Test A and Test B.

Now I want to design a query or a procedure which allows to display data from student table and test_table with condition if student has taken both Test A.

Only test A info needs to displayed along with student info otherwise any test taken info should be displayed or no test info should be displayed if no test available.