I am having a difficult time pinning down an official description of what a test suite is compared to a test plan.
In Test Computer Software they don't even mention suites. (I assume because the book is rather dated)
From IBM they state that:
If each test case represents a piece of a scenario, such as the elements that simulate a user completing a transaction, use a test suite. For instance a test suite might contain four test cases, each with a separate test script: Test case 1: Login, Test case 2: Add New Products, Test case 3: Checkout, Test case 4: Logout
Test suites can identify gaps in a testing effort where the successful completion of one test case must occur before beginning the next test case.
which makes it sound like they are classifying a test suite as something to be run in succession.
In software development, a test suite, less commonly known as a validation suite, is a collection of test cases that are intended to be used to test a software program to show that it has some specified set of behaviours. A test suite often contains detailed instructions or goals for each collection of test cases and information on the system configuration to be used during testing. A group of test cases may also contain prerequisite states or steps, and descriptions of the following tests.
Collections of test cases are sometimes incorrectly termed a test plan, a test script, or even a test scenario.
I also found this explanation:
Fundamentally Test Plan is a logical collection of Test Cases. Lets say you have some test cases that test the Authentication functionality of a website, then you can group all those Test Cases under an Authentication_Test_Plan.
Test Suite on the other hand is an execution unit such as Functional Test, User Acceptance Testing (UAT), Integration Test or Regression Test. These Test Suite can have any combination of Test Cases which are required for the corresponding Testing phase. So 2 Test Suites can actually have the same or widely different Test Cases.
I could continue to give more examples of dissenting opinions, but this has already gone pretty long. I am starting to get concerned that there isn't an actual definition, and everybody just makes up their own definition to fit their preconceived notions. If that is the case I'll just move on, but I'm hoping that isn't the case, and we can pin down what they actually are.