WIP: tests/emulator/poke_around: test setting user.shell

tests/emulator/poke_around.py

@@ -52,3 +52,48 @@ def run(d):
     d.ui.press('enter')
     wait_for(d, 'This is Zip')
     screenshot(d, 'zip-is-still-there')
+
+    def switch_and_relogin():
+        screenshot(d, 'pre-switch')
+        d('input text "nix-on-droid switch"')
+        d.ui.press('enter')
+        screenshot(d, 'post-switch')
+        d('input text "exit"')
+        d.ui.press('enter')
+        nod = d.app('com.termux.nix')
+        nod.launch()
+
+    # change shell: pkgs.fish
+    d('input text "sed -i '
+      r'\'s|## Simply install just the packages|user.shell = pkgs.fish;|\''
+      '.config/nixpkgs/nix-on-droid.nix"')
+    d.ui.press('enter')
+    switch_and_relogin()
+    screenshot(d, 're-login-bare-fish')
+    wait_for(d, 'Welcome to fish, the friendly interactive shell')
+    screenshot(d, 're-login-done-bare-fish')
+
+    # change shell: ${pkgs.fish}, which is a directory
+    d('input text \'sed -i '
+      r'\"s|user.shell = .*|user.shell = \"${pkgs.fish}\";|\"'
+      '.config/nixpkgs/nix-on-droid.nix"')
+    d.ui.press('enter')
+    switch_and_relogin()
+    screenshot(d, 're-login-shell-dir-fallback')
+    wait_for(d, 'Cannot execute shell ')
+    wait_for(d, 'it is a directory.')
+    wait_for(d,
+             'Unlike nixos you should point `user.shell` to the exact binary.')
+    wait_for(d, 'Falling back to bash.')
+    wait_for(d, 'bash-5.2$')
+    screenshot(d, 're-login-done-shell-dir-fallback')
+
+    # change shell: ${pkgs.fish}/bin/fish
+    d('input text "sed -i '
+      r'\'s|user.shell = .*|user.shell = ${pkgs.fish}/bin/fish;|\''
+      '.config/nixpkgs/nix-on-droid.nix"')
+    d.ui.press('enter')
+    switch_and_relogin()
+    screenshot(d, 're-login-fish-bin-fish')
+    wait_for(d, 'Welcome to fish, the friendly interactive shell')
+    screenshot(d, 're-login-done-fish-bin-fish')