Libguestfs - Jan 2019 - Re: [PATCH v2 nbdkit] tests: Add generic ‘requires’ function for test prerequisites.

v1 was here:
https://www.redhat.com/archives/libguestfs/2019-January/thread.html#00198

For v2 I changed most existing prerequisite tests to use the new
mechanism.

I only changed simple tests.  There are a few more complex tests that
don't fit the “requires model” and those are not changed.

I normalized qemu-io/qemu-img testing to always use the --version
flag, where previously we used a mix of --version and --help.

The requires tests are generally done above the cleanup function, to
avoid doing cleanup if we're not going to run the test.

Error messages are sometimes changed, but nothing important.

Tested it on Linux, FreeBSD and OpenBSD.

Rich.

---
 tests/functions.sh.in                  | 17 ++++++++++++++++-
 tests/test-cache-max-size.sh           | 18 +++---------------
 tests/test-data-7E.sh                  |  8 ++------
 tests/test-data-base64.sh              | 12 ++++--------
 tests/test-data-file.sh                |  8 ++------
 tests/test-data-raw.sh                 |  8 ++------
 tests/test-eflags.sh                   | 13 +++++--------
 tests/test-error0.sh                   |  6 +-----
 tests/test-error10.sh                  |  6 +-----
 tests/test-error100.sh                 |  6 +-----
 tests/test-full.sh                     |  8 ++------
 tests/test-ip.sh                       | 21 ++++++---------------
 tests/test-memory-largest-for-qemu.sh  |  8 ++------
 tests/test-memory-largest.sh           |  8 ++------
 tests/test-offset2.sh                  |  8 ++------
 tests/test-parallel-file.sh            | 10 ++--------
 tests/test-parallel-nbd.sh             | 10 ++--------
 tests/test-partition1.sh               | 22 ++++------------------
 tests/test-partition2.sh               |  6 +-----
 tests/test-partitioning1.sh            |  8 ++------
 tests/test-partitioning2.sh            |  8 ++------
 tests/test-partitioning4.sh            |  6 +-----
 tests/test-partitioning5.sh            |  8 ++------
 tests/test-partitioning6.sh            |  6 +-----
 tests/test-pattern-largest-for-qemu.sh |  8 ++------
 tests/test-pattern-largest.sh          |  8 ++------
 tests/test-single.sh                   | 11 ++---------
 tests/test-tls-psk.sh                  | 12 +++---------
 tests/test-tls.sh                      | 12 +++---------
 tests/test-truncate1.sh                |  8 ++------
 tests/test-truncate2.sh                |  8 ++------
 tests/test-truncate3.sh                |  8 ++------
 tests/test-zero.sh                     |  6 +-----
 33 files changed, 87 insertions(+), 233 deletions(-)

diff --git a/tests/functions.sh.in b/tests/functions.sh.in
index 35647f7..289584a 100644
--- a/tests/functions.sh.in
+++ b/tests/functions.sh.in
@@ -1,7 +1,7 @@
 # nbdkit
 # Common functions used by the tests.
 # @configure_input@
-# Copyright (C) 2017-2018 Red Hat Inc.
+# Copyright (C) 2017-2019 Red Hat Inc.
 # All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
@@ -57,6 +57,21 @@ _run_cleanup_hooks ()
 }
 trap _run_cleanup_hooks INT QUIT TERM EXIT ERR
 
+# requires program [args]
+#
+# Check that ‘program [args]’ works.  If not, skip the test.
+# For example to check that qemu-img is available, do:
+#
+# requires qemu-img --version
+requires ()
+{
+    ( "$@" ) </dev/null >/dev/null 2>&1 || {
+        echo "$0: ‘$*’ failed with error code $?"
+        echo "$0: test prerequisite is missing or not working"
+        exit 77
+    }
+}
+
 # start_nbdkit -P pidfile args...
 #
 # Run nbdkit with args and wait for it to start up.  If it fails to
diff --git a/tests/test-cache-max-size.sh b/tests/test-cache-max-size.sh
index f7e743a..8cb5ad1 100755
--- a/tests/test-cache-max-size.sh
+++ b/tests/test-cache-max-size.sh
@@ -36,22 +36,10 @@ set -e
 set -x
 
 # Check that this is a Linux-like system supporting /proc/$pid/fd.
-if ! test -d /proc/self/fd; then
-    echo "$0: not a Linux-like system supporting /proc/\$pid/fd"
-    exit 77
-fi
-
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
+requires test -d /proc/self/fd
+requires qemu-io --version
 # Need the stat command from coreutils.
-if ! stat --version >/dev/null; then
-    echo "$0: missing or broken stat command"
-    exit 77
-fi
+requires stat --version
 
 d=cache-max-size.d
 rm -rf $d
diff --git a/tests/test-data-7E.sh b/tests/test-data-7E.sh
index e27984f..2e48e1b 100755
--- a/tests/test-data-7E.sh
+++ b/tests/test-data-7E.sh
@@ -38,16 +38,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="data-7E.out data-7E.pid data-7E.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit.
 start_nbdkit -P data-7E.pid -U data-7E.sock --export= \
        --filter=partition \
diff --git a/tests/test-data-base64.sh b/tests/test-data-base64.sh
index cc53edf..b755557 100755
--- a/tests/test-data-base64.sh
+++ b/tests/test-data-base64.sh
@@ -37,9 +37,7 @@ source ./functions.sh
 set -e
 set -x
 
-files="data-base64.out data-base64.pid data-base64.sock"
-rm -f $files
-cleanup_fn rm -f $files
+requires qemu-io --version
 
 # Test if the base64 parameter is supported in this build.
 if ! nbdkit data --dump-plugin | grep -sq "data_base64=yes"; then
@@ -47,11 +45,9 @@ if ! nbdkit data --dump-plugin | grep -sq
"data_base64=yes"; then
     exit 77
 fi
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
+files="data-base64.out data-base64.pid data-base64.sock"
+rm -f $files
+cleanup_fn rm -f $files
 
 # Run nbdkit.
 start_nbdkit -P data-base64.pid -U data-base64.sock \
diff --git a/tests/test-data-file.sh b/tests/test-data-file.sh
index ba7288c..c6792e7 100755
--- a/tests/test-data-file.sh
+++ b/tests/test-data-file.sh
@@ -37,16 +37,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="data-file.out data-file.pid data-file.sock data-hello.txt"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 rm -f data-hello.txt
 for i in {0..1000}; do
     echo -n "hello " >> data-hello.txt
diff --git a/tests/test-data-raw.sh b/tests/test-data-raw.sh
index 555b77c..c71afbf 100755
--- a/tests/test-data-raw.sh
+++ b/tests/test-data-raw.sh
@@ -37,16 +37,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="data-raw.out data-raw.pid data-raw.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit.
 start_nbdkit -P data-raw.pid -U data-raw.sock --export "" \
        data raw=123 size=512
diff --git a/tests/test-eflags.sh b/tests/test-eflags.sh
index 5ac5e9e..41793e8 100755
--- a/tests/test-eflags.sh
+++ b/tests/test-eflags.sh
@@ -45,16 +45,13 @@
 source ./functions.sh
 set -e
 
-if ! socat -h >/dev/null; then
-    echo "$0: 'socat' command not available"
-    exit 77
-fi
+requires socat -h
 
 # Check 'od' command exists.
-if ! od </dev/null >/dev/null; then
-    echo "$0: 'od' command not available"
-    exit 77
-fi
+#
+# Note that requires redirects stdin/stdout to /dev/null which
+# prevents od from hanging in this test.
+requires od
 
 files="eflags.out"
 rm -f $files
diff --git a/tests/test-error0.sh b/tests/test-error0.sh
index 93170a9..96a221c 100755
--- a/tests/test-error0.sh
+++ b/tests/test-error0.sh
@@ -35,11 +35,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
+requires qemu-io --version
 
 files="error0.sock error0.pid"
 rm -f $files
diff --git a/tests/test-error10.sh b/tests/test-error10.sh
index 278bae4..d5ab1d4 100755
--- a/tests/test-error10.sh
+++ b/tests/test-error10.sh
@@ -35,11 +35,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
+requires qemu-io --version
 
 files="error10.sock error10.pid"
 rm -f $files
diff --git a/tests/test-error100.sh b/tests/test-error100.sh
index 997de9d..1979717 100755
--- a/tests/test-error100.sh
+++ b/tests/test-error100.sh
@@ -35,11 +35,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
+requires qemu-io --version
 
 files="error100.sock error100.pid"
 rm -f $files
diff --git a/tests/test-full.sh b/tests/test-full.sh
index 171d716..71d9c7c 100755
--- a/tests/test-full.sh
+++ b/tests/test-full.sh
@@ -37,16 +37,12 @@
 source ./functions.sh
 set -e
 
+requires qemu-io --version
+
 files="full.pid full.sock full.out"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with the full plugin.
 start_nbdkit -P full.pid -U full.sock full size=1M
 
diff --git a/tests/test-ip.sh b/tests/test-ip.sh
index d7d5323..f5dcd87 100755
--- a/tests/test-ip.sh
+++ b/tests/test-ip.sh
@@ -37,26 +37,17 @@
 source ./functions.sh
 set -e
 
-rm -f ip.pid ipv4.out ipv6.out
-cleanup_fn rm -f ip.pid ipv4.out ipv6.out
+requires ss --version
+requires ip -V
+requires qemu-img --version
 
-# Don't fail if certain commands aren't available.
-if ! ss --version; then
-    echo "$0: 'ss' command not available"
-    exit 77
-fi
-if ! command -v qemu-img; then
-    echo "$0: 'qemu-img' command not available"
-    exit 77
-fi
 if ! qemu-img --help | grep -- --image-opts; then
     echo "$0: 'qemu-img' command does not have the --image-opts
option"
     exit 77
 fi
-if ! ip -V; then
-    echo "$0: 'ip' command not available"
-    exit 77
-fi
+
+rm -f ip.pid ipv4.out ipv6.out
+cleanup_fn rm -f ip.pid ipv4.out ipv6.out
 
 # Find an unused port to listen on.
 for port in {49152..65535}; do
diff --git a/tests/test-memory-largest-for-qemu.sh
b/tests/test-memory-largest-for-qemu.sh
index 2b56f30..a89fd0d 100755
--- a/tests/test-memory-largest-for-qemu.sh
+++ b/tests/test-memory-largest-for-qemu.sh
@@ -37,16 +37,12 @@
 source ./functions.sh
 set -e
 
+requires qemu-io --version
+
 files="memory-largest-for-qemu.out memory-largest-for-qemu.pid
memory-largest-for-qemu.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with memory plugin.
 # size = (2^63-1) & ~511 which is the largest supported by qemu.
 start_nbdkit -P memory-largest-for-qemu.pid -U memory-largest-for-qemu.sock \
diff --git a/tests/test-memory-largest.sh b/tests/test-memory-largest.sh
index a6c269e..154b331 100755
--- a/tests/test-memory-largest.sh
+++ b/tests/test-memory-largest.sh
@@ -37,16 +37,12 @@
 source ./functions.sh
 set -e
 
+requires qemu-io --version
+
 files="memory-largest.out memory-largest.pid memory-largest.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with memory plugin.
 # size = 2^63-1
 start_nbdkit -P memory-largest.pid -U memory-largest.sock \
diff --git a/tests/test-offset2.sh b/tests/test-offset2.sh
index 4e1ef2b..a958f62 100755
--- a/tests/test-offset2.sh
+++ b/tests/test-offset2.sh
@@ -37,16 +37,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="offset2.out offset2.pid offset2.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin and offset filter in front.
 # 8070450532247927809 = 7E - 1023
 start_nbdkit -P offset2.pid -U offset2.sock \
diff --git a/tests/test-parallel-file.sh b/tests/test-parallel-file.sh
index 1d27f93..0fabd4f 100755
--- a/tests/test-parallel-file.sh
+++ b/tests/test-parallel-file.sh
@@ -34,14 +34,8 @@
 source ./functions.sh
 
 # Check file-data was created by Makefile and qemu-io exists.
-if ! test -f file-data; then
-    echo "$0: missing file-data"
-    exit 77
-fi
-if ! qemu-io --version; then
-    echo "$0: missing qemu-io"
-    exit 77
-fi
+requires test -f file-data
+requires qemu-io --version
 
 cleanup_fn rm -f test-parallel-file.data test-parallel-file.out
 
diff --git a/tests/test-parallel-nbd.sh b/tests/test-parallel-nbd.sh
index e4a2352..cb81ec9 100755
--- a/tests/test-parallel-nbd.sh
+++ b/tests/test-parallel-nbd.sh
@@ -34,14 +34,8 @@
 source ./functions.sh
 
 # Check file-data was created by Makefile and qemu-io exists.
-if ! test -f file-data; then
-    echo "$0: missing file-data"
-    exit 77
-fi
-if ! qemu-io --version; then
-    echo "$0: missing qemu-io"
-    exit 77
-fi
+requires test -f file-data
+requires qemu-io --version
 
 # We require --exit-with-parent to work
 ( nbdkit --exit-with-parent --help ) >/dev/null 2>&1 ||
diff --git a/tests/test-partition1.sh b/tests/test-partition1.sh
index 1bb0240..50d4087 100755
--- a/tests/test-partition1.sh
+++ b/tests/test-partition1.sh
@@ -35,29 +35,15 @@ source ./functions.sh
 set -e
 set -x
 
+requires sfdisk --help
+requires test -r /dev/urandom
+requires qemu-img --version
+
 d="partition1.d"
 rm -rf $d
 cleanup_fn rm -rf $d
 mkdir $d
 
-# Test that sfdisk is available and working.
-if ! sfdisk --help >/dev/null; then
-    echo "$0: missing or broken sfdisk"
-    exit 77
-fi
-
-# Test that /dev/urandom exists and can be read.
-if ! test -r /dev/urandom; then
-    echo "$0: mising or unreadable /dev/urandom"
-    exit 77
-fi
-
-# Test that qemu-img is available and working.
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
-
 test ()
 {
     label=$1
diff --git a/tests/test-partition2.sh b/tests/test-partition2.sh
index 71bac55..4678a5c 100755
--- a/tests/test-partition2.sh
+++ b/tests/test-partition2.sh
@@ -35,11 +35,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-img is available and working.
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
+requires qemu-img --version
 
 files="partition2.log"
 rm -f $files
diff --git a/tests/test-partitioning1.sh b/tests/test-partitioning1.sh
index f705dc8..f0c779d 100755
--- a/tests/test-partitioning1.sh
+++ b/tests/test-partitioning1.sh
@@ -39,16 +39,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-img --version
+
 files="partitioning1.out partitioning1-p1 partitioning1-p2
partitioning1-p3 partitioning1-p4 partitioning1-p5 partitioning1-p6"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-img works
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
-
 # Create some odd-sized partitions.  These exist to test alignment and
 # padding.
 truncate -s 1 partitioning1-p1
diff --git a/tests/test-partitioning2.sh b/tests/test-partitioning2.sh
index 411f392..9f2df11 100755
--- a/tests/test-partitioning2.sh
+++ b/tests/test-partitioning2.sh
@@ -40,16 +40,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires mke2fs -V
+
 files="partitioning2.pid partitioning2.sock partitioning2.fs
partitioning2.p1 partitioning2.p3"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that mke2fs works
-if ! mke2fs -V; then
-    echo "$0: missing or broken mke2fs"
-    exit 77
-fi
-
 # Create partitions before and after.
 truncate -s 1 partitioning2.p1
 truncate -s 10M partitioning2.p3
diff --git a/tests/test-partitioning4.sh b/tests/test-partitioning4.sh
index 8988a5c..8c9a93e 100755
--- a/tests/test-partitioning4.sh
+++ b/tests/test-partitioning4.sh
@@ -43,11 +43,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-img works
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
+requires qemu-img --version
 
 d=partitioning4.d
 rm -rf $d
diff --git a/tests/test-partitioning5.sh b/tests/test-partitioning5.sh
index b4cb6bf..feeb738 100755
--- a/tests/test-partitioning5.sh
+++ b/tests/test-partitioning5.sh
@@ -41,18 +41,14 @@ source ./functions.sh
 set -e
 set -x
 
+requires mke2fs -V
+
 files="partitioning5.pid partitioning5.sock
        partitioning5.fs
        partitioning5.p1 partitioning5.p2 partitioning5.p3 partitioning5.p5
partitioning5.p6 partitioning5.p7 partitioning5.p8 partitioning5.p9
partitioning5.p10 partitioning5.p11 partitioning5.p13"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that mke2fs works
-if ! mke2fs -V; then
-    echo "$0: missing or broken mke2fs"
-    exit 77
-fi
-
 # Create partitions before and after.
 truncate -s 1 partitioning5.p1
 truncate -s 10M partitioning5.p2
diff --git a/tests/test-partitioning6.sh b/tests/test-partitioning6.sh
index 6dbb215..400bd8e 100755
--- a/tests/test-partitioning6.sh
+++ b/tests/test-partitioning6.sh
@@ -43,11 +43,7 @@ source ./functions.sh
 set -e
 set -x
 
-# Test that qemu-img works
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
+requires qemu-img --version
 
 d=partitioning6.d
 rm -rf $d
diff --git a/tests/test-pattern-largest-for-qemu.sh
b/tests/test-pattern-largest-for-qemu.sh
index 1883fe6..93cc1b7 100755
--- a/tests/test-pattern-largest-for-qemu.sh
+++ b/tests/test-pattern-largest-for-qemu.sh
@@ -37,16 +37,12 @@
 source ./functions.sh
 set -e
 
+requires qemu-io --version
+
 files="pattern-largest-for-qemu.out pattern-largest-for-qemu.pid
pattern-largest-for-qemu.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin.
 # size = (2^63-1) & ~511 which is the largest supported by qemu.
 start_nbdkit -P pattern-largest-for-qemu.pid -U pattern-largest-for-qemu.sock \
diff --git a/tests/test-pattern-largest.sh b/tests/test-pattern-largest.sh
index de5e1d7..0b6d272 100755
--- a/tests/test-pattern-largest.sh
+++ b/tests/test-pattern-largest.sh
@@ -37,16 +37,12 @@
 source ./functions.sh
 set -e
 
+requires qemu-io --version
+
 files="pattern-largest.out pattern-largest.pid pattern-largest.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin.
 # size = 2^63-1
 start_nbdkit -P pattern-largest.pid -U pattern-largest.sock \
diff --git a/tests/test-single.sh b/tests/test-single.sh
index 3739df2..3462d3d 100755
--- a/tests/test-single.sh
+++ b/tests/test-single.sh
@@ -35,15 +35,8 @@ source ./functions.sh
 set -e
 set -x
 
-if ! socat -h; then
-    echo "$0: 'socat' command not available"
-    exit 77
-fi
-
-if ! qemu-img --help >/dev/null; then
-    echo "$0: 'qemu-img' command not available"
-    exit 77
-fi
+requires socat -h
+requires qemu-img --version
 
 files="single.sock single.disk"
 rm -f $files
diff --git a/tests/test-tls-psk.sh b/tests/test-tls-psk.sh
index 819d63d..bc4140f 100755
--- a/tests/test-tls-psk.sh
+++ b/tests/test-tls-psk.sh
@@ -35,15 +35,9 @@ source ./functions.sh
 set -e
 set -x
 
-# Don't fail if certain commands aren't available.
-if ! ss --version; then
-    echo "$0: 'ss' command not available"
-    exit 77
-fi
-if ! command -v qemu-img > /dev/null; then
-    echo "$0: 'qemu-img' command not available"
-    exit 77
-fi
+requires ss --version
+requires qemu-img --version
+
 if ! qemu-img --help | grep -- --object; then
     echo "$0: 'qemu-img' command does not have the --object
option"
     exit 77
diff --git a/tests/test-tls.sh b/tests/test-tls.sh
index 114ea35..9f94ba1 100755
--- a/tests/test-tls.sh
+++ b/tests/test-tls.sh
@@ -35,15 +35,9 @@ source ./functions.sh
 set -e
 set -x
 
-# Don't fail if certain commands aren't available.
-if ! ss --version; then
-    echo "$0: 'ss' command not available"
-    exit 77
-fi
-if ! command -v qemu-img > /dev/null; then
-    echo "$0: 'qemu-img' command not available"
-    exit 77
-fi
+requires ss --version
+requires qemu-img --version
+
 if ! qemu-img --help | grep -- --object; then
     echo "$0: 'qemu-img' command does not have the --object
option"
     exit 77
diff --git a/tests/test-truncate1.sh b/tests/test-truncate1.sh
index eb02a69..e09415a 100755
--- a/tests/test-truncate1.sh
+++ b/tests/test-truncate1.sh
@@ -37,16 +37,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="truncate1.out truncate1.pid truncate1.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin and truncate filter in front.
 start_nbdkit -P truncate1.pid -U truncate1.sock \
        --filter=truncate \
diff --git a/tests/test-truncate2.sh b/tests/test-truncate2.sh
index 4a3a89e..f290f29 100755
--- a/tests/test-truncate2.sh
+++ b/tests/test-truncate2.sh
@@ -37,16 +37,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-io --version
+
 files="truncate2.out truncate2.pid truncate2.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-io works
-if ! qemu-io --help >/dev/null; then
-    echo "$0: missing or broken qemu-io"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin and truncate filter in front.
 start_nbdkit -P truncate2.pid -U truncate2.sock \
        --filter=truncate \
diff --git a/tests/test-truncate3.sh b/tests/test-truncate3.sh
index 0ff1cbe..de44a17 100755
--- a/tests/test-truncate3.sh
+++ b/tests/test-truncate3.sh
@@ -38,16 +38,12 @@ source ./functions.sh
 set -e
 set -x
 
+requires qemu-img --version
+
 files="truncate3.out truncate3.pid truncate3.sock"
 rm -f $files
 cleanup_fn rm -f $files
 
-# Test that qemu-img works
-if ! qemu-img --help >/dev/null; then
-    echo "$0: missing or broken qemu-img"
-    exit 77
-fi
-
 # Run nbdkit with pattern plugin and truncate filter in front.
 start_nbdkit -P truncate3.pid -U truncate3.sock \
        --filter=truncate \
diff --git a/tests/test-zero.sh b/tests/test-zero.sh
index 3c3a0ca..2bd4a48 100755
--- a/tests/test-zero.sh
+++ b/tests/test-zero.sh
@@ -35,11 +35,7 @@ source ./functions.sh
 set -x
 set -e
 
-# Check qemu-img exists.
-if ! qemu-img --version; then
-    echo "$0: missing qemu-img"
-    exit 77
-fi
+requires qemu-img --version
 
 files="test-zero.out"
 rm -f $files
-- 
2.20.1

On 1/23/19 9:36 AM, Richard W.M. Jones wrote:
> +++ b/tests/functions.sh.in
> @@ -1,7 +1,7 @@
>  # nbdkit
>  # Common functions used by the tests.
>  # @configure_input@
> -# Copyright (C) 2017-2018 Red Hat Inc.
> +# Copyright (C) 2017-2019 Red Hat Inc.
>  # All rights reserved.
>  #
>  # Redistribution and use in source and binary forms, with or without
> @@ -57,6 +57,21 @@ _run_cleanup_hooks ()
>  }
>  trap _run_cleanup_hooks INT QUIT TERM EXIT ERR
>  
> +# requires program [args]
> +#
> +# Check that ‘program [args]’ works.  If not, skip the test.
> +# For example to check that qemu-img is available, do:
> +#
> +# requires qemu-img --version
> +requires ()
> +{
> +    ( "$@" ) </dev/null >/dev/null 2>&1 || {
> +        echo "$0: ‘$*’ failed with error code $?"
> +        echo "$0: test prerequisite is missing or not working"
> +        exit 77
> +    }
> +}
Updated function looks good.
> +++ b/tests/test-ip.sh
> @@ -37,26 +37,17 @@
>  source ./functions.sh
>  set -e
>  
> -rm -f ip.pid ipv4.out ipv6.out
> -cleanup_fn rm -f ip.pid ipv4.out ipv6.out
> +requires ss --version
> +requires ip -V
> +requires qemu-img --version
>  
> -# Don't fail if certain commands aren't available.
> -if ! ss --version; then
> -    echo "$0: 'ss' command not available"
> -    exit 77
> -fi
> -if ! command -v qemu-img; then
> -    echo "$0: 'qemu-img' command not available"
> -    exit 77
> -fi
>  if ! qemu-img --help | grep -- --image-opts; then
>      echo "$0: 'qemu-img' command does not have the
--image-opts option"
>      exit 77
The old test insists on --image-opts,
>  fi
> -if ! ip -V; then
> -    echo "$0: 'ip' command not available"
> -    exit 77
> -fi
> +
> +rm -f ip.pid ipv4.out ipv6.out
> +cleanup_fn rm -f ip.pid ipv4.out ipv6.out
...but the rewrite does not.  Could be solved with:

requires qemu-img info --image-opts driver=file,filename=functions.sh
> +++ b/tests/test-partitioning2.sh
> @@ -40,16 +40,12 @@ source ./functions.sh
>  set -e
>  set -x
>  
> +requires mke2fs -V
> +
>  files="partitioning2.pid partitioning2.sock partitioning2.fs
partitioning2.p1 partitioning2.p3"
>  rm -f $files
>  cleanup_fn rm -f $files
>  
> -# Test that mke2fs works
> -if ! mke2fs -V; then
> -    echo "$0: missing or broken mke2fs"
> -    exit 77
> -fi
> -
>  # Create partitions before and after.
>  truncate -s 1 partitioning2.p1
'truncate' is not universally available; that may be something for a
future patch to add a requires line for (but not this patch, which
should be just the mechanical rewrites).
> +++ b/tests/test-tls-psk.sh
> @@ -35,15 +35,9 @@ source ./functions.sh
>  set -e
>  set -x
>  
> -# Don't fail if certain commands aren't available.
> -if ! ss --version; then
> -    echo "$0: 'ss' command not available"
> -    exit 77
> -fi
> -if ! command -v qemu-img > /dev/null; then
> -    echo "$0: 'qemu-img' command not available"
> -    exit 77
> -fi
> +requires ss --version
> +requires qemu-img --version
> +
>  if ! qemu-img --help | grep -- --object; then
There might be a way to express this via requires (similar to the way I
checked for --image-opts support above), via a harmless probe of a
known-existing file. But I didn't spend time coming up with such a
working command line probe (I got distracted by the fact that 'qemu-img
info --object nosuch file' has status 1 but no error message on stderr,
oops).

Looks like you're ready to go.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org