feat: Support upgrading 'bpm' directly from the cli

Previously, a user would have to cd into the directory, then run `git pull`
manually. This feature obviates that

Author: hyperupcall

docs/recepies.md

@@ -36,3 +36,9 @@ current shell. After installing a package, you can run:
 ```sh
 include username/repo lib/file.sh
 ```
+
+# Upgrading `bpm`
+
+```sh
+bpm upgrade bpm
+```

pkg/lib/commands/do-upgrade.sh

@@ -1,7 +1,35 @@
 # shellcheck shell=bash
 
 do-upgrade() {
-	if (( $# == 0 )); then
+	local upgrade_bpm='no'
+
+	local -a pkgs=()
+	for arg; do
+		case "$arg" in
+		bpm)
+			upgrade_bpm='yes'
+			;;
+		*)
+			pkgs+=("$arg")
+			;;
+		esac
+	done
+
+	if [ "$upgrade_bpm" = 'yes' ]; then
+		if (( ${#pkgs[@]} > 0 )); then
+			die 'You cannot upgarde bpm and its packages at the same time'
+		fi
+
+		if [ -d "$PROGRAM_LIB_DIR/../../.git" ]; then
+			git -C "$PROGRAM_LIB_DIR/../.." pull
+		else
+			log.error "bpm is not a Git repository"
+		fi
+
+		return
+	fi
+
+	if (( ${#pkgs[@]} == 0 )); then
 		die "You must supply at least one package"
 	fi
 

tests/do-upgrade.bats

@@ -66,3 +66,32 @@ load 'util/init.sh'
 
 	assert [ ! -f "$BPM_INSTALL_BIN/script3.sh" ]
 }
+
+@test "errors when no packages are given" {
+	run do-upgrade
+
+	assert_failure
+	assert_line -p 'You must supply at least one package'
+}
+
+@test "upgrade bpm works" {
+	local pkg='username/package'
+
+	test_util.mock_command 'git'
+
+	run do-upgrade 'bpm'
+
+	assert_success
+	assert_line 'git -C /home/edwin/data/bpm/source/tests/../pkg/lib/../.. pull'
+}
+
+@test "upgrade bpm fails when mixing package names" {
+	local pkg='username/package'
+
+	test_util.mock_command 'git'
+
+	run do-upgrade 'bpm' 'pkg/name'
+
+	assert_failure
+	assert_line -p 'You cannot upgarde bpm and its packages at the same time'
+}

tests/util/init.sh

@@ -15,6 +15,7 @@ export BPM_ORIGIN_DIR="$BPM_TEST_DIR/origin"
 export XDG_DATA_HOME=
 export PATH="$BPM_ROOT/pkg/bin:$PATH"
 
+export PROGRAM_LIB_DIR="$BATS_TEST_DIRNAME/../pkg/lib"
 export BPM_ROOT="$BATS_TEST_DIRNAME/.."
 export BPM_PREFIX="$BPM_TEST_DIR/cellar"
 export BPM_PACKAGES_PATH="$BPM_PREFIX/packages"