tests: repair accidentally deleted tst.pidprobes.sh

My intent when writing the earlier tests was to have
test/unittest/usdt/pidprobes.sh as a sort of shell script library
called by tst.pidprobes.sh, tst.pidargs.sh and tst.pidargmap.sh.
Alas, *.sh is executed as a test by runtest.sh, so
pidprobes.sh was treated as a test, not a library.  So rename it
back to what it was called before and make sure it works when
invoked directly by runtest.sh, but also let it be called by
the other two tests to test other corners of this.

(Also: apply some small review comments that never made it
before the previous patch hit dev.)

Signed-off-by: Nick Alcock <[email protected]>

Author: nickalcock

test/unittest/usdt/tst.pidargmap.sh

@@ -8,4 +8,4 @@
 # This test verifies that USDT and pid probes that share underlying probes
 # do not apply arg mappings (incorrectly) to the pid probes.
 
-exec $(dirname $_test)/pidprobes.sh $1 t t
+exec $(dirname $_test)/tst.pidprobes.sh $1 t t

test/unittest/usdt/tst.pidargs.sh

@@ -8,4 +8,4 @@
 # This test verifies that USDT and pid probes that share underlying probes
 # get the arguments correct for the USDT probes.
 
-exec $(dirname $_test)/pidprobes.sh $1 t ""
+exec $(dirname $_test)/tst.pidprobes.sh $1 t ""

test/unittest/usdt/pidprobes.sh renamed to test/unittest/usdt/tst.pidprobes.sh

@@ -6,11 +6,16 @@
 # http://oss.oracle.com/licenses/upl.
 #
 # This test verifies various properties of USDT and pid probes sharing
-# underlying probes.
+# underlying probes.  With only one argument (as called by runtest.sh),
+# it verifies that USDT and pid probes can share underlying probes.
+#
+# Other tests call back to this one to test arg-mapping behaviour,
+# verify that usdt probes actually fire when overlapped by pid probes,
+# etc.
 
 dtrace=$1
-usdt=$2
-mapping=$3
+usdt=${2:-}
+mapping=${3:-}
 
 # Set up test directory.
 
@@ -86,7 +91,7 @@ fi
 # Check that the program output is 0 when the USDT probe is not enabled.
 # That is, the PYRAMID_ENTRY_ENABLED() is-enabled checks should not pass.
 
-./main standalone > main.out
+./main > main.out
 echo "my result: 0" > main.out.expected
 if ! diff -q main.out main.out.expected > /dev/null; then
 	echo '"my result"' looks wrong when not using DTrace
@@ -131,7 +136,7 @@ fi
 echo "my result: 10" > main.out2.expected
 
 if ! diff -q main.out2 main.out2.expected > /dev/null; then
-	echo '"my result"' looks wrong
+	echo '"my result"' looks wrong when using DTrace
 	echo === got ===
 	cat main.out2
 	echo === expected ===
@@ -297,7 +302,7 @@ if [[ -n $usdt ]]; then
 	fi
 fi
 
-# Sort and check (dropping any wake-up firings from deferred probing).
+# Sort and check.
 
 sort dtrace.out          > dtrace.out.sorted
 sort dtrace.out.expected > dtrace.out.expected.sorted