diff --git a/pkgs/by-name/in/installShellFiles/package.nix b/pkgs/by-name/in/installShellFiles/package.nix
index 12595850c393..87787ad872ee 100644
--- a/pkgs/by-name/in/installShellFiles/package.nix
+++ b/pkgs/by-name/in/installShellFiles/package.nix
@@ -1,4 +1,8 @@
-{ callPackage, makeSetupHook }:
+{
+  lib,
+  callPackage,
+  makeSetupHook,
+}:
 
 # See the header comment in ./setup-hook.sh for example usage.
 let
@@ -6,6 +10,9 @@ let
 in
 setupHook.overrideAttrs (oldAttrs: {
   passthru = (oldAttrs.passthru or { }) // {
-    tests = callPackage ./tests { };
+    tests = lib.packagesFromDirectoryRecursive {
+      inherit callPackage;
+      directory = ./tests;
+    };
   };
 })
diff --git a/pkgs/by-name/in/installShellFiles/tests/default.nix b/pkgs/by-name/in/installShellFiles/tests/default.nix
deleted file mode 100644
index 456edc5c6330..000000000000
--- a/pkgs/by-name/in/installShellFiles/tests/default.nix
+++ /dev/null
@@ -1,147 +0,0 @@
-{
-  lib,
-  runCommandLocal,
-  recurseIntoAttrs,
-  installShellFiles,
-}:
-
-let
-  runTest =
-    name: env: buildCommand:
-    runCommandLocal "install-shell-files--${name}" (
-      {
-        nativeBuildInputs = [ installShellFiles ];
-        meta.platforms = lib.platforms.all;
-      }
-      // env
-    ) buildCommand;
-in
-
-recurseIntoAttrs {
-  # installManPage
-
-  install-manpage = runTest "install-manpage" { } ''
-    mkdir -p doc
-    echo foo > doc/foo.1
-    echo bar > doc/bar.2.gz
-    echo baz > doc/baz.3
-
-    installManPage doc/*
-
-    cmp doc/foo.1 $out/share/man/man1/foo.1
-    cmp doc/bar.2.gz $out/share/man/man2/bar.2.gz
-    cmp doc/baz.3 $out/share/man/man3/baz.3
-  '';
-  install-manpage-outputs =
-    runTest "install-manpage-outputs"
-      {
-        outputs = [
-          "out"
-          "man"
-          "devman"
-        ];
-      }
-      ''
-        mkdir -p doc
-        echo foo > doc/foo.1
-        echo bar > doc/bar.3
-
-        installManPage doc/*
-
-        # assert they didn't go into $out
-        [[ ! -f $out/share/man/man1/foo.1 && ! -f $out/share/man/man3/bar.3 ]]
-
-        # foo.1 alone went into man
-        cmp doc/foo.1 ''${!outputMan:?}/share/man/man1/foo.1
-        [[ ! -f ''${!outputMan:?}/share/man/man3/bar.3 ]]
-
-        # bar.3 alone went into devman
-        cmp doc/bar.3 ''${!outputDevman:?}/share/man/man3/bar.3
-        [[ ! -f ''${!outputDevman:?}/share/man/man1/foo.1 ]]
-
-        touch $out
-      '';
-
-  # installShellCompletion
-
-  install-completion = runTest "install-completion" { } ''
-    echo foo > foo
-    echo bar > bar
-    echo baz > baz
-    echo qux > qux.zsh
-    echo quux > quux
-
-    installShellCompletion --bash foo bar --zsh baz qux.zsh --fish quux
-
-    cmp foo $out/share/bash-completion/completions/foo
-    cmp bar $out/share/bash-completion/completions/bar
-    cmp baz $out/share/zsh/site-functions/_baz
-    cmp qux.zsh $out/share/zsh/site-functions/_qux
-    cmp quux $out/share/fish/vendor_completions.d/quux
-  '';
-  install-completion-output =
-    runTest "install-completion-output"
-      {
-        outputs = [
-          "out"
-          "bin"
-        ];
-      }
-      ''
-        echo foo > foo
-
-        installShellCompletion --bash foo
-
-        # assert it didn't go into $out
-        [[ ! -f $out/share/bash-completion/completions/foo ]]
-
-        cmp foo ''${!outputBin:?}/share/bash-completion/completions/foo
-
-        touch $out
-      '';
-  install-completion-name = runTest "install-completion-name" { } ''
-    echo foo > foo
-    echo bar > bar
-    echo baz > baz
-
-    installShellCompletion --bash --name foobar.bash foo --zsh --name _foobar bar --fish baz
-
-    cmp foo $out/share/bash-completion/completions/foobar.bash
-    cmp bar $out/share/zsh/site-functions/_foobar
-    cmp baz $out/share/fish/vendor_completions.d/baz
-  '';
-  install-completion-inference = runTest "install-completion-inference" { } ''
-    echo foo > foo.bash
-    echo bar > bar.zsh
-    echo baz > baz.fish
-
-    installShellCompletion foo.bash bar.zsh baz.fish
-
-    cmp foo.bash $out/share/bash-completion/completions/foo.bash
-    cmp bar.zsh $out/share/zsh/site-functions/_bar
-    cmp baz.fish $out/share/fish/vendor_completions.d/baz.fish
-  '';
-  install-completion-cmd = runTest "install-completion-cmd" { } ''
-    echo foo > foo.bash
-    echo bar > bar.zsh
-    echo baz > baz.fish
-    echo qux > qux.fish
-
-    installShellCompletion --cmd foobar --bash foo.bash --zsh bar.zsh --fish baz.fish --name qux qux.fish
-
-    cmp foo.bash $out/share/bash-completion/completions/foobar.bash
-    cmp bar.zsh $out/share/zsh/site-functions/_foobar
-    cmp baz.fish $out/share/fish/vendor_completions.d/foobar.fish
-    cmp qux.fish $out/share/fish/vendor_completions.d/qux
-  '';
-  install-completion-fifo = runTest "install-completion-fifo" { } ''
-    installShellCompletion \
-      --bash --name foo.bash <(echo foo) \
-      --zsh --name _foo <(echo bar) \
-      --fish --name foo.fish <(echo baz)
-
-    [[ $(<$out/share/bash-completion/completions/foo.bash) == foo ]] || { echo "foo.bash comparison failed"; exit 1; }
-    [[ $(<$out/share/zsh/site-functions/_foo) == bar ]] || { echo "_foo comparison failed"; exit 1; }
-    [[ $(<$out/share/fish/vendor_completions.d/foo.fish) == baz ]] || { echo "foo.fish comparison failed"; exit 1; }
-  '';
-}
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion-cmd.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion-cmd.nix
new file mode 100644
index 000000000000..a8687ccc2c7d
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion-cmd.nix
@@ -0,0 +1,24 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion-cmd"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    echo foo > foo.bash
+    echo bar > bar.zsh
+    echo baz > baz.fish
+    echo qux > qux.fish
+
+    installShellCompletion --cmd foobar --bash foo.bash --zsh bar.zsh --fish baz.fish --name qux qux.fish
+
+    cmp foo.bash $out/share/bash-completion/completions/foobar.bash
+    cmp bar.zsh $out/share/zsh/site-functions/_foobar
+    cmp baz.fish $out/share/fish/vendor_completions.d/foobar.fish
+    cmp qux.fish $out/share/fish/vendor_completions.d/qux
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion-fifo.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion-fifo.nix
new file mode 100644
index 000000000000..2c777f0fb68a
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion-fifo.nix
@@ -0,0 +1,21 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion-fifo"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    installShellCompletion \
+      --bash --name foo.bash <(echo foo) \
+      --zsh --name _foo <(echo bar) \
+      --fish --name foo.fish <(echo baz)
+
+    [[ $(<$out/share/bash-completion/completions/foo.bash) == foo ]] || { echo "foo.bash comparison failed"; exit 1; }
+    [[ $(<$out/share/zsh/site-functions/_foo) == bar ]] || { echo "_foo comparison failed"; exit 1; }
+    [[ $(<$out/share/fish/vendor_completions.d/foo.fish) == baz ]] || { echo "foo.fish comparison failed"; exit 1; }
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion-inference.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion-inference.nix
new file mode 100644
index 000000000000..9a51965ccecb
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion-inference.nix
@@ -0,0 +1,22 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion-inference"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    echo foo > foo.bash
+    echo bar > bar.zsh
+    echo baz > baz.fish
+
+    installShellCompletion foo.bash bar.zsh baz.fish
+
+    cmp foo.bash $out/share/bash-completion/completions/foo.bash
+    cmp bar.zsh $out/share/zsh/site-functions/_bar
+    cmp baz.fish $out/share/fish/vendor_completions.d/baz.fish
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion-name.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion-name.nix
new file mode 100644
index 000000000000..2473318dee2c
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion-name.nix
@@ -0,0 +1,22 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion-name"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    echo foo > foo
+    echo bar > bar
+    echo baz > baz
+
+    installShellCompletion --bash --name foobar.bash foo --zsh --name _foobar bar --fish baz
+
+    cmp foo $out/share/bash-completion/completions/foobar.bash
+    cmp bar $out/share/zsh/site-functions/_foobar
+    cmp baz $out/share/fish/vendor_completions.d/baz
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion-output.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion-output.nix
new file mode 100644
index 000000000000..380b241e4f01
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion-output.nix
@@ -0,0 +1,27 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion-output"
+  {
+    outputs = [
+      "out"
+      "bin"
+    ];
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    echo foo > foo
+
+    installShellCompletion --bash foo
+
+    # assert it didn't go into $out
+    [[ ! -f $out/share/bash-completion/completions/foo ]]
+
+    cmp foo ''${!outputBin:?}/share/bash-completion/completions/foo
+
+    touch $out
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-completion.nix b/pkgs/by-name/in/installShellFiles/tests/install-completion.nix
new file mode 100644
index 000000000000..2738dd647f56
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-completion.nix
@@ -0,0 +1,26 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-completion"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    echo foo > foo
+    echo bar > bar
+    echo baz > baz
+    echo qux > qux.zsh
+    echo quux > quux
+
+    installShellCompletion --bash foo bar --zsh baz qux.zsh --fish quux
+
+    cmp foo $out/share/bash-completion/completions/foo
+    cmp bar $out/share/bash-completion/completions/bar
+    cmp baz $out/share/zsh/site-functions/_baz
+    cmp qux.zsh $out/share/zsh/site-functions/_qux
+    cmp quux $out/share/fish/vendor_completions.d/quux
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-manpage-outputs.nix b/pkgs/by-name/in/installShellFiles/tests/install-manpage-outputs.nix
new file mode 100644
index 000000000000..4e249a9e5061
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-manpage-outputs.nix
@@ -0,0 +1,36 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-manpage-outputs"
+  {
+    outputs = [
+      "out"
+      "man"
+      "devman"
+    ];
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    mkdir -p doc
+    echo foo > doc/foo.1
+    echo bar > doc/bar.3
+
+    installManPage doc/*
+
+    # assert they didn't go into $out
+    [[ ! -f $out/share/man/man1/foo.1 && ! -f $out/share/man/man3/bar.3 ]]
+
+    # foo.1 alone went into man
+    cmp doc/foo.1 ''${!outputMan:?}/share/man/man1/foo.1
+    [[ ! -f ''${!outputMan:?}/share/man/man3/bar.3 ]]
+
+    # bar.3 alone went into devman
+    cmp doc/bar.3 ''${!outputDevman:?}/share/man/man3/bar.3
+    [[ ! -f ''${!outputDevman:?}/share/man/man1/foo.1 ]]
+
+    touch $out
+  ''
diff --git a/pkgs/by-name/in/installShellFiles/tests/install-manpage.nix b/pkgs/by-name/in/installShellFiles/tests/install-manpage.nix
new file mode 100644
index 000000000000..7b67d0aed94c
--- /dev/null
+++ b/pkgs/by-name/in/installShellFiles/tests/install-manpage.nix
@@ -0,0 +1,23 @@
+{
+  lib,
+  installShellFiles,
+  runCommandLocal,
+}:
+
+runCommandLocal "install-shell-files--install-manpage"
+  {
+    nativeBuildInputs = [ installShellFiles ];
+    meta.platforms = lib.platforms.all;
+  }
+  ''
+    mkdir -p doc
+    echo foo > doc/foo.1
+    echo bar > doc/bar.2.gz
+    echo baz > doc/baz.3
+
+    installManPage doc/*
+
+    cmp doc/foo.1 $out/share/man/man1/foo.1
+    cmp doc/bar.2.gz $out/share/man/man2/bar.2.gz
+    cmp doc/baz.3 $out/share/man/man3/baz.3
+  ''