test: add test runner entry point

tests/testMain.cpp

@@ -0,0 +1,42 @@
+#include "testHarness.h"
+
+#include <cstdio>
+
+namespace vftest {
+
+int failures = 0;
+int checks = 0;
+
+std::vector<TestCase>& registry() {
+    static std::vector<TestCase> cases;
+    return cases;
+}
+
+int registerTest(const char* name, std::function<void()> fn) {
+    registry().push_back({name, std::move(fn)});
+    return 0;
+}
+
+void reportCheck(bool ok, const char* expr, const char* file, int line) {
+    ++checks;
+    if (!ok) {
+        ++failures;
+        std::printf("  FAIL %s:%d  %s\n", file, line, expr);
+    }
+}
+
+} // namespace vftest
+
+int main() {
+    int failedTests = 0;
+    for (auto& test : vftest::registry()) {
+        int before = vftest::failures;
+        test.fn();
+        bool passed = vftest::failures == before;
+        std::printf("[%s] %s\n", passed ? "PASS" : "FAIL", test.name.c_str());
+        if (!passed) ++failedTests;
+    }
+    std::printf("\n%zu tests, %d checks, %d failed checks, %d failed tests\n",
+                vftest::registry().size(), vftest::checks, vftest::failures, failedTests);
+    return vftest::failures == 0 ? 0 : 1;
+}