Add test suite for timezone tests

Previously, when testing the clock command of x52cli, we had forced the
system timezone to UTC. As a result, the offset calculations for clocks
2 and 3 were never computed and always resulted in 0, which hid the bug
when the local time and local standard time did not match (#20).

This commit adds a test case that uses faketime to test setting the
clock to local (Pacific Time) and verifying that the offsets are
computed correctly. Given that the bug is still present as of this
commit, add the test suite to XFAIL_TESTS as well, so that it doesn't
break the CI build.

tests/Makefile.am

@@ -13,7 +13,12 @@ TESTS = \
 	libx52/test_brightness.sh \
 	libx52/test_indicator.sh \
 	libx52/test_mfd.sh \
-	libx52/test_clock.sh
+	libx52/test_clock.sh \
+	libx52/test_timezone.sh
+
+# NOTE: Timezone tests currently fail when local time is daylight time. Once
+# this is fixed, remove the line below.
+XFAIL_TESTS = libx52/test_timezone.sh
 
 EXTRA_DIST = common_infra.sh $(TESTS)
 

tests/common_infra.sh

@@ -106,6 +106,25 @@ find_programs()
     fi
 }
 
+# This is for additional programs that are not needed by every test case
+require_programs()
+{
+    local skip=false
+    for prog in "$@"
+    do
+        if ! command -v "$prog"
+        then
+            echo "Required program '$prog' not found, skipping test suite"
+            skip=true
+        fi
+    done
+
+    if $skip
+    then
+        exit $EXIT_SKIP
+    fi
+}
+
 setup_preload()
 {
     # Find the libusb stub library

tests/libx52/test_timezone.sh

@@ -0,0 +1,68 @@
+#!/bin/bash
+# Timezone tests
+#
+# Copyright (C) 2020 Nirenjan Krishnan (nirenjan@nirenjan.org)
+#
+# SPDX-License-Identifier: GPL-2.0-only WITH Classpath-exception-2.0
+
+source $(dirname $0)/../common_infra.sh
+require_programs faketime
+
+TEST_SUITE_ID="libx52 timezone tests"
+
+# Use the America/Los_Angeles timezone
+# Standard time is UTC-08:00, Daylight time is UTC-07:00
+export TZ=America/Los_Angeles
+
+# All timezone tests use DD-MM-YY and 12hr format
+timezone_test()
+{
+    local datetime="$1"
+
+    TEST_ID="Test setting clock to '$(date --date="$datetime")'"
+
+    local dd=$(date --date="$datetime" +%_d)
+    local mm=$(date --date="$datetime" +%_m)
+    local yy=$(date --date="$datetime" +%_y)
+    local hr=$(date --date="$datetime" +%_H)
+    local mn=$(date --date="$datetime" +%_M)
+
+    local off
+    if [[ "$(date --date="$datetime" +%Z)" == 'PDT' ]]
+    then
+        # Pacific Daylight Time
+        # Default offset for clocks 2 & 3 should be +420 minutes
+        off=420
+    else
+        # Pacific Standard time
+        # Default offset for clocks 2 & 3 should be +480 minutes
+        off=480
+    fi
+
+    local clock_value=$(($hr * 256 + $mn))
+    local date_value=$(($mm * 256 + $dd))
+    local year_value=$yy
+
+    expect_pattern \
+        $X52_CLOCK_DATE_INDEX $(printf '%04x' $date_value) \
+        $X52_CLOCK_YEAR_INDEX $(printf '%04x' $year_value) \
+        $X52_CLOCK_1_INDEX $(printf '%04x' $clock_value) \
+        $X52_CLOCK_2_INDEX $(printf '%04x' $off) \
+        $X52_CLOCK_3_INDEX $(printf '%04x' $off) \
+
+    faketime "$datetime" $X52CLI clock local 12hr ddmmyy
+    verify_output
+}
+
+# Check timezone test for 14:15:16 on the 13th day of every month from
+# January 2017 to December 2019
+
+for year in $(seq 2017 2019)
+do
+    for month in $(seq 1 12)
+    do
+        timezone_test "$(printf '%d-%02d-13 14:15:16' $year $month)"
+    done
+done
+
+verify_test_suite