Always exit with the exit code of the command

Previously, in case a command started successfully, but failed
eventually, pistol would not exit with the exit code of the command.

Fixes #52.

Makefile

@@ -37,6 +37,11 @@ test: pistol
 	@echo application/json \(issue '#'34\):
 	@echo -------------------
 	@./pistol --config tests/config tests/34.json
+	@tput sgr0
+	@echo -------------------
+	@echo exit code \(issue '#'52\):
+	@echo -------------------
+	@./tests/exit-code.sh
 
 deps:
 	go get github.com/c4milo/github-release

VERSION

@@ -1 +1 @@
-0.1.8
+0.1.9

previewer.go

@@ -171,7 +171,7 @@ func (p *Previewer) Write(w io.Writer) (error) {
 			log.Fatalf("We've had issues running your command: %v, %s", p.Command, p.Args)
 			return err
 		}
-		cmd.Wait()
+		return cmd.Wait()
 	} else {
 		// try to match with internal writers
 		internal_writer, err := pistol.MatchInternalWriter(p.MimeType, p.FilePath)

tests/config

@@ -6,3 +6,7 @@ fpath .*/tests/fpath-with-sh$ sh: bat --map-syntax :Markdown --paging=never --st
 text/html elinks -dump -dump-color-mode 1 %pistol-filename%
 # detects: mimetype, sh: yes
 text/plain sh: bat --map-syntax :Markdown --paging=never --style=numbers --color=always %pistol-filename% | head -1
+# Test exit code is non-zero in case a command does not exist:
+application/x-bzip2 not-a-real-command %pistol-filename%
+# Test exit code is non-zero in case a command starts but fails to finish
+fpath .*/tests$ bat %pistol-filename%

tests/exit-code.sh

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+if ./pistol --config tests/config tests/34.json.bz2; then
+	tput setaf 1
+	echo "exit code was not non-zero when testing a non real command"
+	exit 1
+else
+	tput setaf 2
+	echo "exit code was not zero"
+fi
+
+if ./pistol --config tests/config tests; then
+	tput setaf 1
+	echo "exit code was not non-zero when testing a real command with invalid arguments for it"
+	exit 1
+else
+	tput setaf 2
+	echo "exit code was not zero"
+fi
+tput sgr0
+exit 0