build: add recipes for using c8 for tool test coverage reports

tools/make/lib/tools-test-cov/c8.mk

@@ -0,0 +1,61 @@
+#/
+# @license Apache-2.0
+#
+# Copyright (c) 2026 The Stdlib Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#/
+
+# RULES #
+
+#/
+# Runs unit tests for project tools and generates a test coverage report using c8.
+#
+# ## Notes
+#
+# -   Raw TAP output is piped to a TAP reporter.
+# -   This command is useful when wanting to glob for JavaScript test files (e.g., generate a test coverage report for all JavaScript tests for a particular package).
+#
+#
+# @private
+# @param {string} [TESTS_FILTER] - file path pattern
+# @param {*} [FAIL_FAST] - flag indicating whether to stop running tests upon encountering a test failure
+#
+# @example
+# make tools-test-c8
+#
+# @example
+# make tools-test-c8 TESTS_FILTER=".*/doctest/compare-values/.*"
+#/
+tools-test-c8: $(NODE_MODULES)
+ifeq ($(FAIL_FAST), true)
+	$(QUIET) $(FIND_TOOLS_TESTS_CMD) | grep '^[\/]\|^[a-zA-Z]:[/\]' | while read -r test; do \
+		echo ''; \
+		echo "Running test: $$test"; \
+		NODE_ENV="$(NODE_ENV_TEST)" \
+		NODE_PATH="$(NODE_PATH_TEST)" \
+		TEST_MODE=coverage \
+		$(C8) $(c8_flags) $(NODE) $$test | $(TAP_REPORTER) || exit 1; \
+	done
+else
+	$(QUIET) $(FIND_TOOLS_TESTS_CMD) | grep '^[\/]\|^[a-zA-Z]:[/\]' | while read -r test; do \
+		echo ''; \
+		echo "Running test: $$test"; \
+		NODE_ENV="$(NODE_ENV_TEST)" \
+		NODE_PATH="$(NODE_PATH_TEST)" \
+		TEST_MODE=coverage \
+		$(C8) $(c8_flags) $(NODE) $$test | $(TAP_REPORTER) || echo 'Tests failed.'; \
+	done
+endif
+
+.PHONY: tools-test-c8

tools/make/lib/tools-test-cov/javascript.mk

@@ -20,18 +20,40 @@
 
 ifeq ($(JAVASCRIPT_CODE_INSTRUMENTER), istanbul)
 	include $(TOOLS_MAKE_LIB_DIR)/tools-test-cov/istanbul.mk
+else
+ifeq ($(JAVASCRIPT_CODE_INSTRUMENTER), c8)
+	include $(TOOLS_MAKE_LIB_DIR)/tools-test-cov/c8.mk
+endif
 endif
 
 
-# TARGETS #
+# RULES #
 
-# Run unit tests and generate a test coverage report.
+#/
+# Runs JavaScript unit tests for project tools and generates a test coverage report.
 #
-# This target instruments JavaScript source code, runs unit tests, and outputs a test coverage report.
-
+# ## Notes
+#
+# -   Raw TAP output is piped to a TAP reporter.
+# -   This command is useful when wanting to glob for JavaScript test files (e.g., generate a test coverage report for all JavaScript tests for a particular package).
+#
+# @param {string} [TESTS_FILTER] - file path pattern (e.g., `.*/doctest/compare-values/.*`)
+# @param {string} [JAVASCRIPT_CODE_INSTRUMENTER] - JavaScript code instrumenter
+# @param {*} [FAST_FAIL] - flag indicating whether to stop running tests upon encountering a test failure
+#
+# @example
+# make tools-test-javascript-cov
+#
+# @example
+# make tools-test-javascript-cov TESTS_FILTER=".*/doctest/compare-values/.*"
+#/
 tools-test-javascript-cov:
 ifeq ($(JAVASCRIPT_CODE_INSTRUMENTER), istanbul)
 	$(QUIET) NODE_ENV_TEST="$(NODE_ENV_TEST)" NODE_PATH_TEST="$(NODE_PATH_TEST)" NODE_FLAGS_TEST="$(NODE_FLAGS_TEST)" $(MAKE) -f $(this_file) tools-test-istanbul
+else
+ifeq ($(JAVASCRIPT_CODE_INSTRUMENTER), c8)
+	$(QUIET) NODE_ENV_TEST="$(NODE_ENV_TEST)" NODE_PATH_TEST="$(NODE_PATH_TEST)" NODE_FLAGS_TEST="$(NODE_FLAGS_TEST)" $(MAKE) -f $(this_file) tools-test-c8
+endif
 endif
 
 .PHONY: tools-test-javascript-cov