diff --git a/.gitignore b/.gitignore
index bf6116d..d2b0d57 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,8 @@
+.calva/repl.calva-repl
+.clj-kondo/.cache
 .cpcache
+.lsp/.cache
+.portal/vs-code.edn
 .rebl
 .rebl.sh
 .idea/
diff --git a/src/cognitect/test_runner.clj b/src/cognitect/test_runner.clj
index 122e7e8..9263e67 100644
--- a/src/cognitect/test_runner.clj
+++ b/src/cognitect/test_runner.clj
@@ -1,7 +1,10 @@
 (ns cognitect.test-runner
-  (:require [clojure.tools.namespace.find :as find]
+  (:require [cognitect.test-runner.protocols :as p]
+            [clojure.tools.namespace.find :as find]
             [clojure.java.io :as io]
             [clojure.test :as test]
+            [clojure.test.junit :as junit]
+            [clojure.test.tap :as tap]
             [clojure.tools.cli :as cli])
   (:refer-clojure :exclude [test]))
 
@@ -53,12 +56,36 @@
                               (assoc :test (::test %))
                               (dissoc ::test)))))))
 
-(defn- contains-tests?
+(defn- ns-contains-tests?
   "Check if a namespace contains some tests to be executed."
   [ns]
   (some (comp :test meta)
         (-> ns ns-publics vals)))
 
+(defrecord ClojureTestRunner []
+  p/TestRunner
+  (enable-filtering! [_ options nses]
+    (filter-vars! nses (var-filter options)))
+  (contains-tests? [_ _ ns] (ns-contains-tests? ns))
+  (run-tests [this options nses]
+    ;; we only care about junit and tap (other test runners might care about
+    ;; other values)
+    (if-let [outputs (seq (filter #{'junit 'tap} (:output options)))]
+      (doseq [output outputs]
+        (case output
+          junit
+          (junit/with-junit-output
+            (apply test/run-tests (filter #(p/contains-tests? this options %) nses)))
+          tap
+          (tap/with-tap-output
+            (apply test/run-tests (filter #(p/contains-tests? this options %) nses)))))
+      (apply test/run-tests (filter #(p/contains-tests? this options %) nses))))
+  (disable-filtering! [_ _ nses]
+    (restore-vars! nses)))
+
+(defn create-clojure-test-runner []
+  (->ClojureTestRunner))
+
 (defn test
   [options]
   (let [dirs (or (:dir options)
@@ -66,14 +93,24 @@
         nses (->> dirs
                   (map io/file)
                   (mapcat find/find-namespaces-in-dir))
-        nses (filter (ns-filter options) nses)]
+        nses (filter (ns-filter options) nses)
+        tsym (or (:test-runner-fn options)
+                 'cognitect.test-runner/create-clojure-test-runner)
+        t-fn (try
+               (require (symbol (namespace tsym)))
+               (resolve tsym)
+               (catch Throwable t
+                 (println "Unable to find test runner function:" tsym)
+                 (throw t)))
+        ;; create the test runner:
+        trun (t-fn)]
     (println (format "\nRunning tests in %s" dirs))
     (dorun (map require nses))
     (try
-      (filter-vars! nses (var-filter options))
-      (apply test/run-tests (filter contains-tests? nses))
+      (p/enable-filtering! trun options nses)
+      (p/run-tests trun options nses)
       (finally
-        (restore-vars! nses)))))
+        (p/disable-filtering! trun options nses)))))
 
 (defn- parse-kw
   [^String s]
@@ -102,6 +139,11 @@
    ["-e" "--exclude KEYWORD" "Exclude tests with this metadata keyword."
     :parse-fn parse-kw
     :assoc-fn accumulate]
+   ["-t" "--test-runner-fn SYMBOL" "Symbol indicating the test runner function to use."
+    :parse-fn symbol]
+   [nil "--output SYMBOL" "Output format, specific to the selected test runner."
+    :parse-fn symbol
+    :assoc-fn (fn [m k v] (update m k (fnil conj []) v))]
    ["-H" "--test-help" "Display this help message"]])
 
 (defn- help
diff --git a/src/cognitect/test_runner/api.clj b/src/cognitect/test_runner/api.clj
index 162211c..ef26be2 100644
--- a/src/cognitect/test_runner/api.clj
+++ b/src/cognitect/test_runner/api.clj
@@ -4,13 +4,15 @@
     [cognitect.test-runner :as tr]))
 
 (defn- do-test
-  [{:keys [dirs nses patterns vars includes excludes]}]
+  [{:keys [dirs nses patterns vars includes excludes test-runner-fn outputs]}]
   (let [adapted {:dir (when (seq dirs) (set dirs))
                  :namespace (when (seq nses) (set nses))
                  :namespace-regex (when (seq patterns) (map re-pattern patterns))
                  :var (when (seq vars) (set vars))
                  :include (when (seq includes) (set includes))
-                 :exclude (when (seq excludes) (set excludes))}]
+                 :exclude (when (seq excludes) (set excludes))
+                 :test-runner-fn test-runner-fn
+                 :output (when (seq outputs) (vec outputs))}]
     (tr/test adapted)))
 
 (defn test
@@ -22,9 +24,13 @@
   * :vars - coll of fully qualified symbols to run tests on
   * :includes - coll of test metadata keywords to include
   * :excludes - coll of test metadata keywords to exclude
+  * :test-runner-fn - symbol identifying test runner creation function
+  * :outputs - coll of output formats (symbols) to use
 
-  If neither :nses nor :patterns is supplied, use `:patterns [\".*-test$\"]`."
+  If neither :nses nor :patterns is supplied, use `:patterns [\".*-test$\"]`.
+
+  Not all output formats produce a fail/error summary."
   [opts]
-  (let [{:keys [fail error]} (do-test opts)]
+  (let [{:keys [fail error] :or {fail 0, error 0}} (do-test opts)]
     (when (> (+ fail error) 0)
       (throw (ex-info "Test failures or errors occurred." {})))))
diff --git a/src/cognitect/test_runner/protocols.clj b/src/cognitect/test_runner/protocols.clj
new file mode 100644
index 0000000..dd2301c
--- /dev/null
+++ b/src/cognitect/test_runner/protocols.clj
@@ -0,0 +1,7 @@
+(ns cognitect.test-runner.protocols)
+
+(defprotocol TestRunner :extend-via-metadata true
+  (enable-filtering! [this opts nses])
+  (contains-tests? [this opts ns])
+  (run-tests [this opts nses])
+  (disable-filtering! [this opts nses]))