This is a very simple test suite for nix expressions. It should help us set up a good suite of unit tests for our nix-based stuff. Since we allow import from derivation, these tests can also depend on derivations and e.g. use `builtins.readFile` to check outputs. This is a first PoC to get us going, we can always replace it by something different in the future if we don’t like it. Change-Id: I206c7b624db2b1dabd9c73ffce4f87e658919958 Reviewed-on: https://cl.tvl.fyi/c/depot/+/662 Reviewed-by: tazjin <mail@tazj.in> Tested-by: tazjin <mail@tazj.in>
		
			
				
	
	
		
			121 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
			
		
		
	
	
			121 lines
		
	
	
	
		
			3 KiB
		
	
	
	
		
			Nix
		
	
	
	
	
	
| { lib, pkgs, depot, ... }:
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| 
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| # Run a nix testsuite.
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| #
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| # The tests are simple assertions on the nix level,
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| # and can use derivation outputs if IfD is enabled.
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| #
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| # You build a testsuite by bundling assertions into
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| # “it”s and then bundling the “it”s into a testsuite.
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| #
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| # Running the testsuite will abort evaluation if
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| # any assertion fails.
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| #
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| # Example:
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| #
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| #   runTestsuite "myFancyTestsuite" [
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| #     (it "does an assertion" [
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| #       (assertEq "42 is equal to 42" "42" "42")
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| #       (assertEq "also 23" 23 23)
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| #     ])
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| #     (it "frmbls the brlbr" [
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| #       (assertEq true false)
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| #     ])
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| #   ]
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| #
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| # will fail the second it group because true is not false.
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| 
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| let
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|   inherit (depot.nix.yants) sum struct string any unit defun list;
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| 
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|   # rewrite the builtins.partition result
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|   # to use `ok` and `err` instead of `right` and `wrong`.
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|   partitionTests = pred: xs:
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|     let res = builtins.partition pred xs;
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|     in {
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|       ok = res.right;
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|       err = res.wrong;
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|     };
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| 
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|   # The result of an assert,
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|   # either it’s true (yep) or false (nope).
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|   # If it’s nope, we return the left and right
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|   # side of the assert, together with the description.
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|   AssertResult =
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|     sum "AssertResult" {
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|       yep = struct "yep" {
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|         test = string;
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|       };
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|       nope = struct "nope" {
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|         test = string;
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|         left = any;
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|         right = any;
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|       };
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|     };
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| 
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|   # Result of an it. An it is a bunch of asserts
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|   # bundled up with a good description of what is tested.
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|   ItResult =
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|     struct "ItResult" {
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|       it-desc = string;
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|       asserts = list AssertResult;
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|     };
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| 
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|   # assert that left and right values are equal
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|   assertEq = defun [ string any any AssertResult ]
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|     (desc: left: right:
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|       if left == right
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|       then { yep = { test = desc; }; }
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|       else { nope = {
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|         test = desc;
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|         inherit left right;
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|       };
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|     });
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| 
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|   # Annotate a bunch of asserts with a descriptive name
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|   it = desc: asserts: {
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|     it-desc = desc;
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|     inherit asserts;
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|   };
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| 
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|   # Run a bunch of its and check whether all asserts are yep.
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|   # If not, abort evaluation with `throw`
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|   # and print the result of the test suite.
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|   #
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|   # Takes a test suite name as first argument.
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|   runTestsuite = defun [ string (list ItResult) unit ]
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|     (name: itResults:
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|       let
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|         goodAss = ass: {
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|           good = AssertResult.match ass {
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|             yep = _: true;
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|             nope = _: false;
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|           };
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|           x = ass;
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|         };
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|         goodIt = it: {
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|           inherit (it) it-desc;
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|           asserts = partitionTests (ass:
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|             AssertResult.match ass {
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|               yep = _: true;
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|               nope = _: false;
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|             }) it.asserts;
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|         };
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|         goodIts = partitionTests (it: (goodIt it).asserts.err == []);
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|         res = goodIts itResults;
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|       in
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|         if res.err == []
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|         then {}
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|         # TODO(Profpatsch): pretty printing of results
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|         # and probably also somewhat easier to read output
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|         else throw
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|           ( "testsuite ${name} failed!\n"
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|           + lib.generators.toPretty {} res));
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| 
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| in {
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|   inherit
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|     assertEq
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|     it
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|     runTestsuite
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|     ;
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| }
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