Update macOS 11 to 12 in GitHub Actions CI

Since macOS 12 no longer provides `/usr/bin/python`, but provides
`/usr/bin/python3`, add code to handle this case to testing scripts.

.github/workflows/main.yml

@@ -36,7 +36,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ 'ubuntu-22.04', 'macos-11' ]
+        os: [ 'ubuntu-22.04', 'macos-12' ]
         python: [ '3.7', '3.8', '3.9', '3.10', '3.11' ]
     name: Python ${{ matrix.python }} (${{ matrix.os }})
     steps:

csv2txf_test.sh

@@ -23,6 +23,12 @@ fi
 
 declare -i num_failures=0
 
+# macOS 12+ doesn't provide /usr/bin/python, but provides /usr/bin/python3
+PYTHON="python"
+if ! [[ -f "/usr/bin/python" ]] && [[ -f "/usr/bin/python3" ]]; then
+  PYTHON="python3"
+fi
+
 # Args:
 #   $0: file with expected stdout
 #   $*: command-line flags for csv2txf.py for this run
@@ -32,15 +38,15 @@ function test_csv2txf() {
 
   if [ $regen -ne 0 ]; then
     echo "Updating ${expected_out} ..."
-    ./csv2txf.py "$@" -o "${expected_out}"
+    "${PYTHON}" ./csv2txf.py "$@" -o "${expected_out}"
     return
   fi
 
   echo "Testing ${expected_out} ..."
   local base="$(basename ${expected_out})"
   local out="$(mktemp /tmp/csv2txf.${base}.out.XXXXXX)"
   local err="$(mktemp /tmp/csv2txf.${base}.err.XXXXXX)"
-  ./csv2txf.py "$@" -o "${out}" 2> "${err}"
+  "${PYTHON}" ./csv2txf.py "$@" -o "${out}" 2> "${err}"
 
   diff -u "${expected_out}" "${out}" || {
     cat "${err}"

run_all_tests.sh

@@ -16,15 +16,16 @@
 
 declare -i success=0
 
+# macOS 12+ doesn't provide /usr/bin/python, but provides /usr/bin/python3
+PYTHON="python"
+if ! [[ -f "/usr/bin/python" ]] && [[ -f "/usr/bin/python3" ]]; then
+  PYTHON="python3"
+fi
+
 for test in *_test.* ; do
   test_out="$(mktemp "/tmp/csv2txf.${test}.XXXXXX")"
-  if [[ ${test} =~ _test.py ]] && [ -n "${PYTHON:-}" ]; then
-    echo -n "Testing ${test} (with ${PYTHON}) ... "
-    "${PYTHON}" "./${test}" > "${test_out}" 2>&1
-  else
-    echo -n "Testing ${test} ... "
-    "./${test}" > "${test_out}" 2>&1
-  fi
+  echo -n "Testing ${test} ... "
+  "${PYTHON}" "./${test}" > "${test_out}" 2>&1
   if [[ $? -eq 0 ]]; then
     echo "PASSED."
   else