run-tests: scope :report-counters to the call

Previously an inner (run-tests ...) inflated the outer caller's
counters and emitted a summary showing cumulative totals. Match
clojure.test by saving the caller's :report-counters on entry,
running the tests against fresh counters, then restoring the saved
counters before returning. The returned counters map reflects only
this run's tests.

Smoke test gets a regression: inner run-tests must not change outer
counters; its returned summary must equal its own scope.

Author: borkdude

bb/tasks.clj

@@ -87,7 +87,7 @@
     (shell "node" "node_cli.js" "compile" src)
     (let [out (:out (shell {:out :string} "node" out-file))]
       (fs/delete out-file)
-      (assert (str/includes? out "Ran 6 tests containing 10 assertions") out)
+      (assert (str/includes? out "Ran 7 tests containing 13 assertions") out)
       (assert (str/includes? out "1 failures, 0 errors") out))))
 
 (defn test-squint []

src/squint/test.cljs

@@ -179,15 +179,24 @@
       ((join-fixtures once-fixtures) run-all)
       (run-all))))
 
+(def ^:private fresh-counters {:test 0 :pass 0 :fail 0 :error 0})
+
 (defn run-tests
   "Runs tests and reports a summary. Accepts any of:
    - no args: run every registered test across all namespaces.
    - namespace name strings: run tests registered under each given ns.
    - explicit test fns: run those fns directly.
    Initializes the env if none is set. Tests are grouped by their ns
    (from deftest's metadata) so each ns's once-fixtures wrap that ns's
-   tests, matching cljs.test. Returns (or resolves to, for async tests)
-   the :report-counters summary map."
+   tests, matching cljs.test.
+
+   Counters are scoped to this call: the caller's :report-counters are
+   saved on entry and restored before return, so an inner run-tests
+   doesn't pollute an outer run's totals (matches clojure.test, where
+   *report-counters* is rebound per test-ns).
+
+   Returns (or resolves to, for async tests) the :report-counters
+   summary map for this run."
   [& args]
   (let [test-vars (cond
                     (empty? args)
@@ -197,6 +206,8 @@
                     :else
                     args)
         _ (when (nil? *current-env*) (set-env! (empty-env)))
+        saved-counters (:report-counters (get-current-env))
+        _ (update-current-env! [:report-counters] (constantly fresh-counters))
         ;; preserve insertion order while grouping by ns
         groups (reduce (fn [acc v]
                          (let [k (:ns (meta v))]
@@ -210,7 +221,9 @@
                              nil groups))
         finish (fn [_]
                  (report {:type :summary})
-                 (:report-counters (get-current-env)))
+                 (let [counters (:report-counters (get-current-env))]
+                   (update-current-env! [:report-counters] (constantly saved-counters))
+                   counters))
         chain (run-groups)]
     (if (async? chain)
       (.then chain finish)

test-resources/cljs_test_smoke.cljs

@@ -70,6 +70,20 @@
               "b-once-setup" "b-1" "b-once-teardown"] @log)
           "each ns's once-fixture wraps only that ns's tests"))))
 
+(deftest run-tests-counter-isolation-test
+  (testing "an inner run-tests doesn't disturb the caller's counters"
+    (let [before (:report-counters (t/get-current-env))
+          inner-result (t/run-tests
+                        (with-meta (fn [] (is true)) {:name "inner-1" :ns "x"})
+                        (with-meta (fn [] (is true)) {:name "inner-2" :ns "x"}))
+          after (:report-counters (t/get-current-env))]
+      (is (= before after)
+          "outer counters are restored after run-tests returns")
+      (is (= 2 (:test inner-result))
+          "returned summary reflects only the inner run's tests")
+      (is (= 2 (:pass inner-result))
+          "returned summary reflects only the inner run's passes"))))
+
 (defn ^:async -main []
   (t/set-env! (t/empty-env))
   (t/test-var math-test)
@@ -78,6 +92,7 @@
   (js-await (t/test-var async-test))
   (t/test-var per-ns-each-fixtures-test)
   (t/test-var per-ns-once-fixtures-test)
+  (t/test-var run-tests-counter-isolation-test)
   (t/report {:type :summary}))
 
 (-main)