From 5bd7ea2aa3f6f102d0208d48c08a93b55d49c529 Mon Sep 17 00:00:00 2001
From: Matt Schreiber <schreibah@gmail.com>
Date: Wed, 15 Jan 2020 14:06:16 -0500
Subject: [PATCH] Clean up "work" directory before "arion up"

to ensure that the subtests defined in tests/arion-test/default.nix do
not inadvertently re-use the arion-compose.nix, arion-pkgs.nix, etc. set
up during the _previous_ subtest.

Previously, each subtest attempted to clean itself up by doing
the following:

    cd work && [...snip...] && rm -rf work

This removes the directory "work/work", while leaving "work" itself
intact.  Subsequent subtests would then run:

    cp -r ${../../examples/some-example} work

thereby copying the contents of "some-example" into "work/work" rather
than into "work".

As a result, all subtests but the first simply reapplied the Arion
configuration set up by the first subtest, because this configuration
persisted within the "work" directory used as the working directory for
"arion up", etc.

This commit corrects the issue by:

    1. Removing "work" rather than "work/work", and
    2. Adding certain flags to the "cp" invocation to ensure it reliably
       copies files into "work" rather than "work/work": (a) "-f"
       ("--force"), to overwrite destination files if they already
       exist, and (b) "-T" ("--no-target-directory") to copy the
       *contents* of the source directory to "work" rather than copying
       the source directory itself as a subdirectory of "work".

Additionally, this commit factors out code common to all subtests into a
reusable subtest generator coderef.
---
 tests/arion-test/default.nix | 33 ++++++++++++++-------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/tests/arion-test/default.nix b/tests/arion-test/default.nix
index caf892a..5bea4fe 100644
--- a/tests/arion-test/default.nix
+++ b/tests/arion-test/default.nix
@@ -40,27 +40,22 @@ in
     $machine->fail("curl localhost:8000");
     $machine->succeed("docker --version");
 
-    subtest "minimal", sub {
-      $machine->succeed("cp -r ${../../examples/minimal} work && cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion up -d");
-      $machine->waitUntilSucceeds("curl localhost:8000");
-      $machine->succeed("cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion down && rm -rf work");
-      $machine->waitUntilFails("curl localhost:8000");
+    my $makeSubtest = sub {
+      my ( $subtestName, $exampleSrc, @codeRefs ) = @_;
+
+      subtest $subtestName => sub {
+        $machine->succeed("rm -rf work && cp -frT $exampleSrc work && cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion up -d");
+        $machine->waitUntilSucceeds("curl localhost:8000");
+        $_->() for @codeRefs;
+        $machine->succeed("cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion down");
+        $machine->waitUntilFails("curl localhost:8000");
+      };
     };
 
-    subtest "full-nixos", sub {
-      $machine->succeed("cp -r ${../../examples/full-nixos} work && cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion up -d");
-      $machine->waitUntilSucceeds("curl localhost:8000");
-      # Also test exec with defaultExec
+    $makeSubtest->("minimal", "${../../examples/minimal}");
+    $makeSubtest->("full-nixos", "${../../examples/full-nixos}", sub {
       $machine->succeed("cd work && export NIX_PATH=nixpkgs='${pkgs.path}' && (echo 'nix run -f ~/h/arion arion -c arion exec webserver'; echo 'target=world; echo Hello \$target'; echo exit) | script /dev/null | grep 'Hello world'");
-      $machine->succeed("cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion down && rm -rf work");
-      $machine->waitUntilFails("curl localhost:8000");
-    };
-
-    subtest "nixos-unit", sub {
-      $machine->succeed("cp -r ${../../examples/nixos-unit} work && cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion up -d");
-      $machine->waitUntilSucceeds("curl localhost:8000");
-      $machine->succeed("cd work && NIX_PATH=nixpkgs='${pkgs.path}' arion down && rm -rf work");
-      $machine->waitUntilFails("curl localhost:8000");
-    };
+    });
+    $makeSubtest->("nixos-unit", "${../../examples/nixos-unit}");
   '';
 }