Initial version of testing + Nix flake

Makefile

@@ -1,6 +1,19 @@
 all:
 
 lint:
-	@find apply push lib -type f -not -iname '*.*' | xargs shellcheck -s bash
-	@shellcheck -s dash run
-	@echo -e "\033[032mOK\033[0m"
+	@find apply push -type f -not -iname '*.*' | xargs shellcheck -s bash
+	@find run lib -type f -not -iname '*.*' | xargs shellcheck -s dash
+	@printf "\033[032mLINT OK\033[0m\n\n"
+
+test: lint test-dash test-bash
+
+test-ash:
+	@cd test && ash ./lib_test.sh
+
+test-dash:
+	@cd test && dash ./lib_test.sh
+
+test-bash:
+	@cd test && bash ./lib_test.sh
+
+.PHONY: lint test test-dash test-bash

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1623875721,
+        "narHash": "sha256-A8BU7bjS5GirpAUv4QA+QnJ4CceLHkcXdRp4xITDB0s=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "f7e004a55b120c02ecb6219596820fcd32ca8772",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1625874246,
+        "narHash": "sha256-7cGgcysIXz/j/lRpJn7cNJjf0+k7sQ5EuGn62252Svw=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "45fc7d4a35c5343e58541a7847f6415654ccbb37",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-unstable",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,52 @@
+{
+  description = "Simple zero-dependency tool to provision *nix machines";
+
+  inputs.nixpkgs.url = "nixpkgs/nixos-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:
+      let pkgs = nixpkgs.legacyPackages.${system}; in
+      rec {
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            dash
+            gnumake
+            shellcheck
+          ];
+        };
+
+        checks = let
+          commonDeps = with pkgs; [ gnumake shellcheck ];
+
+        in {
+          bash = pkgs.runCommand "lint" {
+            src = ./.;
+            nativeBuildInputs = commonDeps ++ (with pkgs; [ bash ]);
+          } ''
+            export SHELL="${pkgs.bash}/bin/bash"
+            make -C "$src" test-bash
+            touch "$out"
+          '';
+
+          dash = pkgs.runCommand "lint" {
+            src = ./.;
+            nativeBuildInputs = commonDeps ++ (with pkgs; [ dash ]);
+          } ''
+            export SHELL="${pkgs.dash}/bin/dash"
+            make -C "$src" test-dash
+            touch "$out"
+          '';
+
+          busybox = pkgs.runCommand "lint" {
+            src = ./.;
+            nativeBuildInputs = commonDeps ++ (with pkgs; [ busybox ]);
+          } ''
+            export SHELL="${pkgs.busybox}/bin/ash"
+            make -C "$src" test-ash
+            touch "$out"
+          '';
+        };
+      }
+    );
+}

lib

@@ -1,46 +1,42 @@
-# shellcheck shell=bash
+# shellcheck shell=dash
 # vim: ft=sh
 
-# Support functions
+# substitute replaces all occurances of one string with another in the provided
+# file, writing to the specified output file.
+substitute() {
+    local input="$1"
+    local output="$2"
 
-function ssh_version() {
-    ssh -V 2>&1 | perl -ne '/^OpenSSH_(\d+\.\d+)/ and print "$1";'
+    shift 2
+
+    # TODO: real parsing
+    local search="$1"
+    local replace="$2"
+
+        #-v RS="$(printf "\0")" \
+    awk \
+        -v srch="$search" \
+        -v repl="$replace" \
+        -v RS="" \
+        -v ORS="" \
+        '{ gsub(srch, repl, $0); print $0 }' \
+        < "$input" > "$output"
 }
 
-function ssh_back() {
-    local remote="$1"
-    local timeout=60
-    local port=0
+# substituteInPlace works like substitute but operates in-place on the provided
+# file
+substituteInPlace() {
+    local fpath="$1"
     shift
 
-    case $(ssh_version) in
-        5.*)
-            port=55555
-			# shellcheck disable=SC2029
-            ssh -f -R "$port":127.0.0.1:22 "$remote" sleep "$timeout" >/dev/null 2>&1
-            ;;
-        *)
-			# shellcheck disable=SC2029
-            port="$(ssh -f -R 0:127.0.0.1:22 "$remote" sleep "$timeout" 2>&1 >/dev/null | head -1 | perl -ne '/Allocated port (\d+)/ and print "$1"')"
-            ;;
-    esac
+    local tmpfile
+    tmpfile="$(mktemp)"
     
-    local args="-o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -p $port"
-	# shellcheck disable=SC2029
-    [[ -n "$port" ]] && ssh -A "$remote" "SSH_BACK_PORT=$port; SSH_BACK_USER=$USER; SSH_BACK_ARGS='$args'; $*" 2> >(grep -v "Permanently added")
+    if ! substitute "$fpath" "$tmpfile" "$@"; then
+        rm "$tmpfile"
+        return $?
+    fi
+
+    # Overwrite now that we've succeeded
+    mv "$tmpfile" "$fpath"
 }
-
-# Fallback functions
-
-if ! which systemctl >/dev/null; then
-function systemctl() {
-    case "$1" in
-        start|stop|restart|reload)
-            service "$2" "$1"
-            ;;
-        *)
-            false
-            ;;
-    esac
-}
-fi

test/lib_test.sh

@@ -0,0 +1,69 @@
+#!/bin/sh
+# shellcheck shell=dash
+
+# Load code to be tested
+. ../lib
+
+oneTimeSetUp() {
+    printf "[INFO] Current shell is: %s\n" "$(cat /proc/$$/cmdline | tr '\0' '\n' | head -n1)"
+    printf "[INFO] Utility paths:\n"
+    for util in awk sed grep; do
+        printf "%8s: %s\n" "$util" "$(which "$util")"
+    done
+}
+
+setUp() {
+    TEST_TMPDIR="$(mktemp -d)"
+    touch "$TEST_TMPDIR/.apply_test_dir"
+}
+
+tearDown() {
+    if test -f "$TEST_TMPDIR/.apply_test_dir"; then
+        rm -rf "$TEST_TMPDIR"
+    fi
+}
+
+testSubstitute_Basic() {
+    echo "hello world" > "$TEST_TMPDIR/input.txt"
+    substitute \
+        "$TEST_TMPDIR/input.txt" \
+        "$TEST_TMPDIR/output.txt" \
+        "hello" "goodbye"
+
+    assertEquals "goodbye world" "$(cat "$TEST_TMPDIR/output.txt")"
+}
+
+testSubstitute_Multi() {
+    echo "hello hello hello" > "$TEST_TMPDIR/input.txt"
+    substitute \
+        "$TEST_TMPDIR/input.txt" \
+        "$TEST_TMPDIR/output.txt" \
+        "hello" "hi"
+
+    assertEquals "hi hi hi" "$(cat "$TEST_TMPDIR/output.txt")"
+}
+
+testSubstitute_Multiline() {
+    printf "hello\nworld\nhello\nworld\n" > "$TEST_TMPDIR/input.txt"
+
+    substitute \
+        "$TEST_TMPDIR/input.txt" \
+        "$TEST_TMPDIR/output.txt" \
+        "hello\nworld" "$(printf "greetings\nall")"
+
+    assertEquals \
+        "$(printf "greetings\nall\ngreetings\nall")" \
+        "$(cat "$TEST_TMPDIR/output.txt")"
+}
+
+testSubstituteInPlace() {
+    echo "hello hello hello" > "$TEST_TMPDIR/sub.txt"
+    substituteInPlace \
+        "$TEST_TMPDIR/sub.txt" \
+        "hello" "hi"
+
+    assertEquals "hi hi hi" "$(cat "$TEST_TMPDIR/sub.txt")"
+}
+
+# Load shUnit2
+. ./shunit2