Make it easier to override Behat format

Only set `--format progress` if not already provided via CLI. Improves cross-OS compatibility

Author: swissspidy

bin/run-behat-tests

@@ -134,4 +134,16 @@ if [[ "${WP_CLI_TEST_COVERAGE}" == "true" ]] && vendor/bin/behat --help 2>/dev/n
 fi
 
 # Run the functional tests.
-vendor/bin/behat --snippets-for="WP_CLI\Tests\Context\FeatureContext" --format progress "$BEHAT_TAGS" --strict "${BEHAT_EXTRA_ARGS[@]}" "$@"
+FORMAT_SPECIFIED=false
+for arg in "$@"; do
+	if [[ "$arg" == "--format"* ]]; then
+		FORMAT_SPECIFIED=true
+		break
+	fi
+done
+
+if [ "$FORMAT_SPECIFIED" = true ]; then
+	vendor/bin/behat --snippets-for="WP_CLI\Tests\Context\FeatureContext" "$BEHAT_TAGS" --strict "${BEHAT_EXTRA_ARGS[@]}" "$@"
+else
+	vendor/bin/behat --snippets-for="WP_CLI\Tests\Context\FeatureContext" --format progress "$BEHAT_TAGS" --strict "${BEHAT_EXTRA_ARGS[@]}" "$@"
+fi