fetchNextcloudApp: refactor for testing

pkgs/build-support/fetchnextcloudapp/default.nix

···
   ...
 }:
 {
+  name ?
+    if appName == null || appVersion == null then null else "nextcloud-app-${appName}-${appVersion}",
   url,
   hash ? "",
   sha256 ? "",
···
   license,
   patches ? [ ],
   description ? null,
+  longDescription ? description,
   homepage ? null,
   maintainers ? [ ],
   teams ? [ ],
   unpack ? false, # whether to use fetchzip rather than fetchurl
 }:
-applyPatches (
-  {
-    inherit patches;
-    src = (if unpack then fetchzip else fetchurl) {
-      inherit
-        url
-        hash
-        sha256
-        sha512
-        ;
-      meta = {
-        license = lib.licenses.${license};
-        longDescription = description;
-        inherit homepage maintainers teams;
-      }
-      // lib.optionalAttrs (description != null) {
-        longDescription = description;
-      }
-      // lib.optionalAttrs (homepage != null) {
-        inherit homepage;
-      };
+applyPatches {
+  ${if name == null then null else "name"} = name;
+  inherit patches;
+
+  src = (if unpack then fetchzip else fetchurl) {
+    inherit url;
+    ${if hash == "" then null else "hash"} = hash;
+    ${if sha256 == "" then null else "sha256"} = sha256;
+    ${if sha512 == "" then null else "sha512"} = sha512;
+
+    meta = {
+      license = lib.licenses.${license};
+      ${if description == null then null else "description"} = description;
+      ${if longDescription == null then null else "longDescription"} = longDescription;
+      ${if homepage == null then null else "homepage"} = homepage;
+      inherit maintainers teams;
     };
-    prePatch = ''
-      if [ ! -f ./appinfo/info.xml ]; then
-        echo "appinfo/info.xml doesn't exist in $out, aborting!"
-        exit 1
-      fi
-    '';
-  }
-  // lib.optionalAttrs (appName != null && appVersion != null) {
-    name = "nextcloud-app-${appName}-${appVersion}";
-  }
-)
+  };
+  prePatch = ''
+    if [ ! -f ./appinfo/info.xml ]; then
+      echo "appinfo/info.xml doesn't exist in $out, aborting!"
+      exit 1
+    fi
+  '';
+}

pkgs/build-support/fetchnextcloudapp/tests.nix

···
 }:
 
 {
-  simple-sha512 = testers.invalidateFetcherByDrvHash (fetchNextcloudApp {
+  simple-sha512 = testers.invalidateFetcherByDrvHash fetchNextcloudApp {
     appName = "phonetrack";
     appVersion = "0.8.2";
     license = "agpl3Plus";
     sha512 = "f67902d1b48def9a244383a39d7bec95bb4215054963a9751f99dae9bd2f2740c02d2ef97b3b76d69a36fa95f8a9374dd049440b195f4dad2f0c4bca645de228";
     url = "https://github.com/julien-nc/phonetrack/releases/download/v0.8.2/phonetrack-0.8.2.tar.gz";
-  });
-  simple-sha256 = testers.invalidateFetcherByDrvHash (fetchNextcloudApp {
+  };
+  simple-sha256 = testers.invalidateFetcherByDrvHash fetchNextcloudApp {
     appName = "phonetrack";
     appVersion = "0.8.2";
     license = "agpl3Plus";
     sha256 = "7c4252186e0ff8e0b97fc3d30131eeadd51bd2f9cc6aa321eb0c1c541f9572c0";
     url = "https://github.com/julien-nc/phonetrack/releases/download/v0.8.2/phonetrack-0.8.2.tar.gz";
-  });
+  };
 }