diff --git a/project.clj b/project.clj
index 8a948ae..3e48fde 100644
--- a/project.clj
+++ b/project.clj
@@ -3,6 +3,9 @@
   :url "https://github.com/jank-lang/clojure-test-suite"
   :license {:name "MPL 2.0"
             :url "https://www.mozilla.org/en-US/MPL/2.0/"}
+  :clr {:main-cmd      ["Clojure.Main"]
+        :compile-cmd   ["Clojure.Compile"]}
   :dependencies [[org.clojure/clojure "1.12.0"]
                  [org.clojure/clojurescript "1.12.42"]]
-  :plugins [[com.jakemccrary/lein-test-refresh "0.25.0"]])
+  :plugins [[com.jakemccrary/lein-test-refresh "0.25.0"]
+            [lein-clr "0.2.2"]])
diff --git a/test/clojure/core_test/num.cljc b/test/clojure/core_test/num.cljc
index aab3d2e..9727c04 100644
--- a/test/clojure/core_test/num.cljc
+++ b/test/clojure/core_test/num.cljc
@@ -1,26 +1,140 @@
 (ns clojure.core-test.num
-  (:require [clojure.test :as t :refer [deftest is]]
-            [clojure.core-test.portability #?(:cljs :refer-macros :default :refer) [when-var-exists]]))
+  (:require [clojure.test :as t :refer [are deftest is testing]]
+            [clojure.core-test.portability
+             #?(:cljs :refer-macros :default :refer) [when-var-exists]]))
+
+(defn f [])
+
+#?(:bb
+   nil
+
+   :clj
+   (do
+    (definterface IChecker
+      (isLong [^long l])
+      (isLong [^Object l])
+
+      (isDouble [^double d])
+      (isDouble [^Object d]))
+
+   (deftype Checker []
+     IChecker
+     (isLong [_this ^long _l] true)
+     (isLong [_this ^Object _l] false)
+     (isDouble [_this ^double _d] true)
+     (isDouble [_this ^Object _d] false))))
 
 (when-var-exists num
  (deftest test-num
-   #?@(:cljs []
-       :clj
-       ;; The compiler should pass `x` as a primitive to `num`.
-       [(let [x 1.0]
-          (is (instance? java.lang.Double (num x))))
-        (let [x 1]
-          (is (instance? java.lang.Long (num x))))
-        ;; `BigInt` and `BigDecimal` are always boxed and `num` just returns them as-is.
-        (is (instance? clojure.lang.BigInt (num 1N)))
-        (is (instance? java.math.BigDecimal (num 1.0M)))]
-       :cljr
-       ;; The compiler should pass `x` as a primitive to `num`.
-       [(let [x 1.0]
-          (is (instance? System.Double (num x))))
-        (let [x 1]
-          (is (instance? System.Int64 (num x))))
-        ;; `BigInt` and `BigDecimal` are always boxed and `num` just returns them as-is.
-        (is (instance? clojure.lang.BigInt (num 1N)))
-        (is (instance? clojure.lang.BigDecimal (num 1.0M)))]
-       :default (is false "TODO test num"))))
+   (testing "positive cases"
+     #?@(:bb
+         [(is (NaN? (num ##NaN)))
+          (are [n] (and (= n (num n))
+                        (= (type n) (type (num n))))
+            0
+            0.1
+            1/2
+            1N
+            1.0M
+            (short 1)
+            (byte 1)
+            (int 1)
+            (long 1)
+            (float 1.0)
+            (double 1.0)
+            nil
+            ##Inf)]
+
+         :cljs
+         []
+
+         :clj
+         [(testing "longs"
+            (let [l       (long 1)
+                  L       (num l)
+                  checker (Checker.)]
+              (is (.isLong checker l))
+              (is (false? (.isLong checker L)))))
+          (testing "doubles"
+            (let [d       (double 1.0)
+                  D       (num d)
+                  checker (Checker.)]
+              (is (.isDouble checker d))
+              (is (false? (.isDouble checker D)))))
+          ;; `BigInt` and `BigDecimal` are always boxed and `num` just returns them as-is.
+          (is (instance? clojure.lang.BigInt (num 1N)))
+          (is (instance? java.math.BigDecimal (num 1.0M)))]
+
+         :cljr [(is (NaN? (num ##NaN)))
+                (is (= (byte 1) (num (byte 1))))
+                (is (= System.UInt64 (type (num (byte 1)))))
+                (are [n] (and (= n (num n))
+                              (= (type (num n)) System.Int64))
+                  (short 1)
+                  (int 1))
+                (are [n] (and (= n (num n))
+                              (= (type n) (type (num n))))
+                  0
+                  0.1
+                  1/2
+                  1N
+                  1.0M
+                  (long 1)
+                  (float 1.0)
+                  (double 1.0)
+                  nil
+                  ##Inf)]
+
+         ;; By default assume that other platforms are no-ops for numeric inputs
+         :default [(is (NaN? (num ##NaN)))
+                   (are [n] (and (= n (num n))
+                                 (= (type n) (type (num n))))
+                     0
+                     0.1
+                     1/2
+                     1N
+                     1.0M
+                     (short 1)
+                     (byte 1)
+                     (int 1)
+                     (long 1)
+                     (float 1.0)
+                     (double 1.0)
+                     nil
+                     ##Inf)])
+     (testing "exceptions thrown"
+       ;; [[num]] is *almost* a true no-op in `cljr`, equivalent to [[identity]],
+       ;; except that it will upcast to System.Int64/System.UInt64
+       #?@(:cljs
+           []
+
+           :cljr
+           [(are [x] (and (= x (num x))
+                          (= (type x) (type (num x))))
+              f
+              {}
+              #{}
+              []
+              '()
+              \1
+              \a
+              ""
+              "1"
+              'a
+              #"")
+            (is (fn? (num (fn []))))]
+
+           :default
+           [(are [x] (thrown? Exception (num x))
+              (fn [])
+              f
+              {}
+              #{}
+              []
+              '()
+              \1
+              \a
+              ""
+              "1"
+              'a
+              #"")])))))