Add new test module: test/errors

To make sure an invalid command is detected as such, and an error
message is shown to the user.

Covers the problems found in issues #3 and #48.

CHANGELOG.md

@@ -79,6 +79,12 @@
 - Bugfix: Add support for escaped chars in `y` command.
   [#11](https://github.com/aureliojargas/sedsed/issues/11)
 
+- Bugfix: Raise syntax error for unknown `s///` flags.
+  [#3](https://github.com/aureliojargas/sedsed/issues/3)
+
+- Bugfix: Detect and show error on incomplete `s` and `y` commands.
+  [#48](https://github.com/aureliojargas/sedsed/issues/48)
+
 
 ## [Version 1.1][] released in 2019-05-25
 

test/errors/invalid-commands.txt

@@ -0,0 +1,19 @@
+u
+s
+s/
+s//
+s/foo
+s/foo\/foo
+s/foo/bar
+s/foo/bar\/bar
+s/foo/bar/@
+s/foo/bar/@g
+s/foo/bar/g@
+s/foo/bar//
+s/foo/bar/w
+y
+y/
+y//
+y/a
+y/a/b
+y/a/b/g

test/errors/run

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# Always run the tests from this script's folder
+cd "$(dirname "$0")" || exit 1
+
+# Read default configuration
+# shellcheck source=test/_include.sh
+source ../_include.sh
+
+# Run sedsed for each invalid command.
+# Each test is ok if sedsed raises an error message.
+while read -r line
+do
+    test_message "Testing $line"
+    output=$($sedsed -e "$line" || true)
+    if ! echo "$output" | grep -q '^ERROR:'
+    then
+        failed=1
+        echo 'TEST FAILED'
+        echo "$output"
+    fi
+done < invalid-commands.txt
+
+tests_clean_up
+tests_exit