Add a VM test for S3BinaryCacheStore

Fixes #11238.

tests/nixos/default.nix

@@ -146,4 +146,6 @@ in
   functional_root = runNixOSTestFor "x86_64-linux" ./functional/as-root.nix;
 
   user-sandboxing = runNixOSTestFor "x86_64-linux" ./user-sandboxing;
+
+  s3-binary-cache-store = runNixOSTestFor "x86_64-linux" ./s3-binary-cache-store.nix;
 }

tests/nixos/nix-copy-closure.nix

@@ -1,6 +1,6 @@
 # Test ‘nix-copy-closure’.
 
-{ lib, config, nixpkgs, hostPkgs, ... }:
+{ lib, config, nixpkgs, ... }:
 
 let
   pkgs = config.nodes.client.nixpkgs.pkgs;

tests/nixos/s3-binary-cache-store.nix

@@ -0,0 +1,63 @@
+{ lib, config, nixpkgs, ... }:
+
+let
+  pkgs = config.nodes.client.nixpkgs.pkgs;
+
+  pkgA = pkgs.cowsay;
+
+  accessKey = "BKIKJAA5BMMU2RHO6IBB";
+  secretKey = "V7f1CwQqAcwo80UEIJEjc5gVQUSSx5ohQ9GSrr12";
+  env = "AWS_ACCESS_KEY_ID=${accessKey} AWS_SECRET_ACCESS_KEY=${secretKey}";
+
+  storeUrl = "s3://my-cache?endpoint=http://server:9000&region=eu-west-1";
+
+in {
+  name = "nix-copy-closure";
+
+  nodes =
+    { server =
+        { config, lib, pkgs, ... }:
+        { virtualisation.writableStore = true;
+          virtualisation.additionalPaths = [ pkgA ];
+          environment.systemPackages = [ pkgs.minio-client ];
+          nix.extraOptions = "experimental-features = nix-command";
+          services.minio = {
+            enable = true;
+            region = "eu-west-1";
+            rootCredentialsFile = pkgs.writeText "minio-credentials-full" ''
+              MINIO_ROOT_USER=${accessKey}
+              MINIO_ROOT_PASSWORD=${secretKey}
+            '';
+          };
+          networking.firewall.allowedTCPPorts = [ 9000 ];
+        };
+
+      client =
+        { config, pkgs, ... }:
+        { virtualisation.writableStore = true;
+          nix.extraOptions = "experimental-features = nix-command";
+        };
+    };
+
+  testScript = { nodes }: ''
+    # fmt: off
+    start_all()
+
+    # Create a binary cache.
+    server.wait_for_unit("minio")
+
+    server.succeed("mc config host add minio http://localhost:9000 ${accessKey} ${secretKey} --api s3v4")
+    server.succeed("mc mb minio/my-cache")
+
+    server.succeed("${env} nix copy --to '${storeUrl}' ${pkgA}")
+
+    # Copy a package from the binary cache.
+    client.fail("nix path-info ${pkgA}")
+
+    client.succeed("${env} nix store info --store '${storeUrl}' >&2")
+
+    client.succeed("${env} nix copy --no-check-sigs --from '${storeUrl}' ${pkgA}")
+
+    client.succeed("nix path-info ${pkgA}")
+  '';
+}