add tests

test/bad/string.nix

@@ -0,0 +1 @@
+"This isn't a test suite!"

test/it.test.nix

@@ -0,0 +1,11 @@
+{ it, ... }:
+[
+  (it "test's itself???" rec {
+    expected = {success = true; msg = "test's itself???";};
+    actual = 
+      (it "test's itself???" {
+        expected = expected;
+        actual = expected;
+      });
+  })
+]

test/run.test.nix

@@ -0,0 +1,12 @@
+{ it, ... }:
+let
+  pkgs = import <nixpkgs> {}; # impure ¯\_(ツ)_/¯
+  run = import ../tix/run.nix pkgs;
+  output = run [ ./it.test.nix ];
+in
+[
+  (it "makes a derivation called test" {
+    expected = "test";
+    actual = output.name;
+  })
+]

test/test.test.nix

@@ -0,0 +1,18 @@
+{ it, ... }:
+let
+  test = import ../tix/test.nix;
+in
+[
+  (it "get's test results" {
+    expected = [{"msg" = "test's itself???"; "success"= true;}];
+    actual = ( test ./it.test.nix ).results;
+  })
+  (it "has a path" {
+    actual = builtins.typeOf ( test ./it.test.nix ).path;
+    expected = "path";
+  })
+  (it "fails to build non test" {
+    actual = ( test ./bad/string.nix );
+    throws = true;
+  })
+]