tests run hermetically via nix

flake.nix

@@ -26,6 +26,7 @@
   outputs = flakes: let
     self = flakes.self.packages.x86_64-linux;
     nixpkgs = flakes.nixpkgs.legacyPackages.x86_64-linux.pkgsStatic;
+    nixpkgs-dyn = flakes.nixpkgs.legacyPackages.x86_64-linux;
     gourou-src = flakes.gourou-src;
     updfparser-src = flakes.updfparser-src;
     base64-src = flakes.base64-src;
@@ -146,5 +147,21 @@
       '' ];
     };
     defaultPackage.x86_64-linux = self.knock;
+    packages.x86_64-linux.tests = nixpkgs-dyn.stdenv.mkDerivation {
+      name = "tests";
+      src = ./tests;
+      buildInputs = [ (nixpkgs-dyn.python3.withPackages(p: [
+        p.beautifulsoup4
+        p.requests
+      ])) ];
+      patchPhase = ''
+        substituteInPlace tests.py --replace "./result/bin/knock" "${self.knock}/bin/knock"
+      '';
+      installPhase = ''
+        mkdir -p $out/bin
+        cp tests.py $out/bin/tests
+        chmod +x $out/bin/tests
+      '';
+    };
   };
 }

readme.md

@@ -52,7 +52,7 @@ nix flake update
 ### Testing
 
 ```
-./tests/test.py
+nix run .#tests -- ./tests/workspace
 ```
 
 Test books can be found [here](https://www.adobe.com/solutions/ebook/digital-editions/sample-ebook-library.html).

tests/tests.py

@@ -1,13 +1,25 @@
-#! /usr/bin/env nix-shell
-#! nix-shell -i python3 -p python3 python310Packages.beautifulsoup4 python310Packages.requests
+#!/usr/bin/env python3
 
 from bs4 import BeautifulSoup
 from urllib.parse import urlparse
 from pathlib import Path
 import requests, sys, subprocess, shutil, os
 
-knock_path = Path(__file__).parent.parent.joinpath("result/bin/knock")
-workspace = Path(__file__).parent.joinpath("workspace")
+knock = Path("./result/bin/knock")
+
+if not knock.exists():
+    print("error: " + str(knock) + " does not exist", file=sys.stderr)
+    sys.exit()
+
+if len(sys.argv) != 2:
+    print(
+        "error: missing required argument: directory in which to perform the tests",
+        file=sys.stderr
+    )
+    sys.exit()
+
+print("Testing " + str(knock))
+workspace = Path(sys.argv[1])
 
 if workspace.exists():
     shutil.rmtree(workspace)
@@ -35,7 +47,7 @@ for i, link in enumerate(links):
     r = requests.get(link)
     open(file, "wb").write(r.content)
 
-    result = subprocess.run([knock_path, file])
+    result = subprocess.run([knock, file])
 
     if result.returncode != 0:
         print("Failed")