[ovs-dev] [PATCH] tests: Skip tests that need "normal" diff if not available.

[Ben Pfaff]

busybox diff does not support "normal" diff format, only the unified
format.  A few OVS tests rely on "normal" format, so those would fail.
This commit avoids the problem by skipping tests that require "normal"
format if it is not available.

Reported-by: Stuart Cardall <developer at it-offshore.co.uk>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2018-March/046460.html
Signed-off-by: Ben Pfaff <blp at ovn.org>
---
 tests/atlocal.in      | 10 ++++++++++
 tests/ovsdb-server.at |  5 +++++
 2 files changed, 15 insertions(+)

diff --git a/tests/atlocal.in b/tests/atlocal.in
index 55f9333eee08..2721a588cb90 100644
--- a/tests/atlocal.in
+++ b/tests/atlocal.in
@@ -170,6 +170,16 @@ find_command tcpdump
 
 CURL_OPT="-g -v --max-time 1 --retry 2 --retry-delay 1 --connect-timeout 1"
 
+# Determine whether "diff" supports "normal" diffs.  (busybox diff does not.)
+diff () {
+    busybox diff "$@"
+}
+if echo xyzzy | diff /dev/null - | grep '^>' >/dev/null; then
+    DIFF_SUPPORTS_NORMAL_FORMAT=yes
+else
+    DIFF_SUPPORTS_NORMAL_FORMAT=no
+fi
+
 # Turn off proxies.
 unset http_proxy
 unset https_proxy
diff --git a/tests/ovsdb-server.at b/tests/ovsdb-server.at
index 2781a14004eb..cbbccab5e5db 100644
--- a/tests/ovsdb-server.at
+++ b/tests/ovsdb-server.at
@@ -1455,6 +1455,7 @@ AT_BANNER([OVSDB -- ovsdb-server replication table-exclusion])
 m4_define([OVSDB_CHECK_REPLICATION],
    [AT_SETUP([$1])
    AT_KEYWORDS([ovsdb server tcp replication table-exclusion])
+   AT_SKIP_IF([test $DIFF_SUPPORTS_NORMAL_FORMAT = no])
    $2 > schema
    AT_CHECK([ovsdb-tool create db1 schema], [0], [stdout], [ignore])
    AT_CHECK([ovsdb-tool create db2 schema], [0], [stdout], [ignore])
@@ -1532,6 +1533,8 @@ AT_CLEANUP
 #ovsdb-server/set-sync-exclude-tables command
 AT_SETUP([ovsdb-server/set-sync-exclude-tables])
 AT_KEYWORDS([ovsdb server replication set-exclude-tables])
+AT_SKIP_IF([test $DIFF_SUPPORTS_NORMAL_FORMAT = no])
+
 replication_schema > schema
 AT_CHECK([ovsdb-tool create db1 schema], [0], [stdout], [ignore])
 AT_CHECK([ovsdb-tool create db2 schema], [0], [stdout], [ignore])
@@ -1619,6 +1622,8 @@ AT_CLEANUP
 #ovsdb-server/disconnect-active-server command
 AT_SETUP([ovsdb-server/disconnect-active-server])
 AT_KEYWORDS([ovsdb server replication disconnect-active-server])
+AT_SKIP_IF([test $DIFF_SUPPORTS_NORMAL_FORMAT = no])
+
 replication_schema > schema
 AT_CHECK([ovsdb-tool create db1 schema], [0], [stdout], [ignore])
 AT_CHECK([ovsdb-tool create db2 schema], [0], [stdout], [ignore])
-- 
2.16.1