Make install.sh run unattended and survive a reinstall

README.md

@@ -24,7 +24,7 @@ Or use `./run.sh`, which also does a `git pull`, installs the dependencies (pyga
 
 To play in a pygame window instead, install pygame and change `INTERFACE_TYPE` near the top of `src/fishE.py` from `UIType.CONSOLE` to `UIType.PYGAME`. The two browser front-ends are started differently; see [Play in your browser](#play-in-your-browser) below.
 
-On a Debian-based machine, `install.sh` (run as root) clones the game into `/usr/games/FishE` and adds a `fishe` command that runs `./run.sh` there; `uninstall.sh` removes both.
+On a Debian-based machine, `install.sh` (run as root) clones the game into `/usr/games/FishE` and adds a `fishe` command that runs `./run.sh` there; `uninstall.sh` removes both. It runs without prompting and is safe to run again: a second run updates the existing clone with `git pull` rather than cloning over it.
 
 ## Features
 

install.sh

@@ -1,12 +1,24 @@
-mkdir /usr/games
+#!/bin/sh
+# Usage: sudo sh install.sh
+# Safe to run again: an existing install is updated rather than cloned over.
+set -e
+
+INSTALL_DIR=/usr/games/FishE
+
+mkdir -p /usr/games
 
 apt-get update
-apt-get install git
-cd /usr/games && git clone https://github.com/Stephenson-Software/FishE
+apt-get install -y git
 
-echo "cd /usr/games/FishE && ./run.sh" > /bin/fishe
-chmod +x /usr/games/FishE/run.sh
+if [ -d "$INSTALL_DIR/.git" ]; then
+    echo "Existing install found in $INSTALL_DIR - updating it."
+    git -C "$INSTALL_DIR" pull
+else
+    git clone https://github.com/Stephenson-Software/FishE "$INSTALL_DIR"
+fi
+
+echo "cd $INSTALL_DIR && ./run.sh" > /bin/fishe
+chmod +x "$INSTALL_DIR/run.sh"
 chmod +x /bin/fishe
 
 echo "Installation complete. Type 'fishe' to play."
-

tests/test_installScript.py

@@ -0,0 +1,100 @@
+"""install.sh must run unattended, and must survive being run a second time.
+
+The script needs root and changes /usr/games and /bin, so neither CI nor a
+contributor's test run can execute it. These tests assert its contract from the
+text instead: a shell to run it under, stopping at the first failure, no step
+that waits on a prompt, and an existing install updated rather than cloned over.
+"""
+
+import os
+
+REPOSITORY_ROOT = os.path.normpath(os.path.join(os.path.dirname(__file__), ".."))
+
+
+def readInstallScript():
+    with open(os.path.join(REPOSITORY_ROOT, "install.sh"), encoding="utf-8") as script:
+        return script.read()
+
+
+def commandLines(script):
+    """The lines of the script that run something, with comments and blank
+    lines dropped so a mention in prose can't stand in for the real thing."""
+    commands = []
+    for line in script.splitlines():
+        stripped = line.strip()
+        if stripped and not stripped.startswith("#"):
+            commands.append(stripped)
+    return commands
+
+
+def test_install_sh_names_its_shell():
+    # prepare
+    script = readInstallScript()
+
+    # call
+    firstLine = script.splitlines()[0]
+
+    # check
+    assert firstLine == "#!/bin/sh"
+
+
+def test_install_sh_stops_at_the_first_failure():
+    # prepare
+    script = readInstallScript()
+
+    # call
+    commands = commandLines(script)
+
+    # check
+    assert "set -e" in commands
+    # before anything that installs or writes, so a failed step can't leave
+    # /bin/fishe pointing at a directory that was never cloned
+    assert commands.index("set -e") < min(
+        index for index, command in enumerate(commands) if "apt-get" in command
+    )
+
+
+def test_install_sh_does_not_fail_on_an_existing_games_directory():
+    # prepare
+    script = readInstallScript()
+
+    # call
+    mkdirCommands = [
+        command for command in commandLines(script) if command.startswith("mkdir")
+    ]
+
+    # check
+    assert mkdirCommands
+    for command in mkdirCommands:
+        assert command.startswith("mkdir -p ")
+
+
+def test_install_sh_does_not_wait_on_an_apt_prompt():
+    # prepare
+    script = readInstallScript()
+
+    # call
+    installCommands = [
+        command for command in commandLines(script) if "apt-get install" in command
+    ]
+
+    # check
+    assert installCommands
+    for command in installCommands:
+        assert " -y " in command
+
+
+def test_install_sh_updates_an_existing_install_instead_of_cloning_over_it():
+    # prepare
+    script = readInstallScript()
+
+    # call
+    commands = commandLines(script)
+    cloneLine = next(
+        index for index, command in enumerate(commands) if "git clone" in command
+    )
+
+    # check
+    assert 'if [ -d "$INSTALL_DIR/.git" ]; then' in commands[:cloneLine]
+    assert 'git -C "$INSTALL_DIR" pull' in commands[:cloneLine]
+    assert commands[cloneLine - 1] == "else"