Use spago install workaround to test.dhall file

Author: JordanMartinez

test.dhall

@@ -1,17 +1,21 @@
-{ name = "node-event-emitters-test"
-, dependencies =
-  [ "aff"
-  , "effect"
-  , "either"
-  , "foldable-traversable"
-  , "functions"
-  , "nullable"
-  , "prelude"
-  , "refs"
-  , "spec"
-  , "tuples"
-  , "unsafe-coerce"
-  ]
-, packages = ./packages.dhall
-, sources = [ "src/**/*.purs", "test/**/*.purs" ]
-}
+let config = ./spago.dhall
+
+-- This hack only works because I know how [email protected] works.
+-- When we run `spago -x test.dhall install`, the package(s) installed
+-- will be added to the `spagoHack` dependencies array, but Spago
+-- will say the config file was not updated. It's lying.
+-- Then when we run `spago -x test.dhall build`,
+-- the final expression in the `in` block will be used.
+let spagoHack =
+      { name = "node-event-emitters-test"
+      , dependencies =
+        [ "aff", "foldable-traversable", "maybe", "refs", "spec", "tuples" ]
+      , packages = ./packages.dhall
+      , sources = [ "test/**/*.purs" ]
+      }
+
+in  { name = spagoHack.name
+    , dependencies = spagoHack.dependencies # config.dependencies
+    , packages = ./packages.dhall
+    , sources = spagoHack.sources # config.sources
+    }