Add first set of basic lua api tests

There are two types of lua tests here:

1. Tests are formed from a <test>.in, <test>.ref and <test>.out triplet. The
   <test>.in file is opened by vis, some operatations are performed and the
   modified file is written to <test>.out. The new <test>.out is compared to
   <test>.ref and the test passes if they are identical.

2. Tests are formed from a single <test>.true file. This file is created by the
   lua code in the test. It contains a single line per test case, this single
   line should be `true` if the test case passed. The <test>.true file is
   checked to ensure it contains only `true` lines and if so, the test passes.

1 files changed, 42 insertions, 0 deletions

diff --git a/lua/test.sh b/lua/test.sh
new file mode 100644
index 0000000..bfc686e
--- /dev/null
+++ b/lua/test.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+
+export VIS_PATH=.
+export VIS_THEME=theme
+printf "<Escape>Q:q<Enter>" | ../util/keys | vis
+
+TESTS_OK=0
+TESTS_RUN=0
+
+ref_files=$(find . -type f -name "*.ref")
+
+for ref in $ref_files; do
+	TESTS_RUN=$((TESTS_RUN + 1))
+	out=${ref%.ref}.out
+	printf "%-30s" "$ref"
+	if cmp $ref $out 2> /dev/null; then
+		printf "PASS\n"
+		TESTS_OK=$((TESTS_OK + 1))
+	else
+		printf "FAIL\n"
+		diff -u $ref $out
+	fi
+done
+
+true_files=$(find . -type f -name "*.true")
+
+for t in $true_files; do
+	TESTS_RUN=$((TESTS_RUN + 1))
+	printf "%-30s" "$t"
+	if ! grep -v true $t > /dev/null; then
+		printf "PASS\n"
+		TESTS_OK=$((TESTS_OK + 1))
+	else
+		printf "FAIL\n"
+		grep -vn true $t
+	fi
+done
+
+printf "Tests ok %d/%d\n" $TESTS_OK $TESTS_RUN
+
+# set exit status
+[ $TESTS_OK -eq $TESTS_RUN ]