diff --git a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a sh test script should be invoked with the specified shell. b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a sh test script should be invoked with the specified shell.
index 728fab3..3ba7be7 100755
--- a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a sh test script should be invoked with the specified shell.	
+++ b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a sh test script should be invoked with the specified shell.	
@@ -2,8 +2,8 @@
 
 # Assuming that urchin was invoked with `-s bash`, this script should be being run with bash.
 
-this_shell=$(ps -o comm= -p $$ && :)
+this_shell=$(ps -o pid,comm | sed -n "s/^ *$$//p" | cut -d\  -f2)
 
 echo "Running shell: $this_shell"
 
-[ "$(basename "$this_shell")" = '.special-shell' ]
+basename "$this_shell" | grep .special-shell
diff --git a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a shebang-less test script should be invoked with the specified shell. b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a shebang-less test script should be invoked with the specified shell.
index 6676bad..74a2aa1 100755
--- a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a shebang-less test script should be invoked with the specified shell.	
+++ b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, a shebang-less test script should be invoked with the specified shell.	
@@ -1,9 +1,10 @@
 # By design, this file has no shebang line.
+set -e
 
 # Assuming that urchin was invoked with `-s bash`, this script should be being run with bash.
 
-this_shell=$(ps -o comm= -p $$ && :)
+this_shell=$(ps -o pid,comm | sed -n "s/^ *$$//p" | cut -d\  -f2)
 
 echo "Running shell: $this_shell"
 
-[ "$(basename "$this_shell")" = '.special-shell' ]
+basename "$this_shell" | grep .special-shell
diff --git a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, the TEST_SHELL environment variable should be set to the specified shell too. b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, the TEST_SHELL environment variable should be set to the specified shell too.
index c28b5e1..c10da8e 100755
--- a/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, the TEST_SHELL environment variable should be set to the specified shell too.	
+++ b/tests/Cross-shell testing/.test-run-by-specified-shell/With -s, the TEST_SHELL environment variable should be set to the specified shell too.	
@@ -2,8 +2,9 @@
 
 # Assuming that urchin was invoked with `-s bash`, $TEST_SHELL should contain 'bash'.
 
-echo "Running shell: $(ps -o comm= -p $$ && :)"
+this_shell=$(ps -o pid,comm | sed -n "s/^ *$$//p" | cut -d\  -f2)
+echo "Running shell: $this_shell"
 
 echo "\$TEST_SHELL: $TEST_SHELL"
 
-[ "$(basename "$this_shell")" = '.special-shell' ]
+basename "$this_shell" | grep .special-shell