4 files changed, 18 insertions, 6 deletions
diff --git a/test-suite/unit-tests/clib/inteq.ml b/test-suite/unit-tests/clib/inteq.ml
index c07ec293f0..89717c79d5 100644
--- a/test-suite/unit-tests/clib/inteq.ml
+++ b/test-suite/unit-tests/clib/inteq.ml
@@ -1,5 +1,7 @@
 open Utest
 
+let log_out_ch = open_log_out_ch __FILE__
+
 let eq0 = mk_bool_test "clib-inteq0"
             "Int.equal on 0"
             (Int.equal 0 0)
@@ -10,4 +12,4 @@ let eq42 = mk_bool_test "clib-inteq42"
 
 let tests = [ eq0; eq42 ]
 
-let _ = run_tests __FILE__ tests
+let _ = run_tests __FILE__ log_out_ch tests
diff --git a/test-suite/unit-tests/clib/unicode_tests.ml b/test-suite/unit-tests/clib/unicode_tests.ml
index 9ae405977b..95316ad3aa 100644
--- a/test-suite/unit-tests/clib/unicode_tests.ml
+++ b/test-suite/unit-tests/clib/unicode_tests.ml
@@ -1,5 +1,7 @@
 open Utest
 
+let log_out_ch = open_log_out_ch __FILE__
+
 let unicode0 = mk_eq_test "clib-unicode0"
                  "split_at_first_letter, first letter is character"
                  None
@@ -12,4 +14,4 @@ let unicode1 = mk_eq_test "clib-unicode1"
 
 let tests = [ unicode0; unicode1 ]
 
-let _ = run_tests __FILE__ tests
+let _ = run_tests __FILE__ log_out_ch tests
diff --git a/test-suite/unit-tests/src/utest.ml b/test-suite/unit-tests/src/utest.ml
index 069e6a4bf3..0cb1780ec9 100644
--- a/test-suite/unit-tests/src/utest.ml
+++ b/test-suite/unit-tests/src/utest.ml
@@ -42,10 +42,12 @@ let run_one logit test =
   let results = perform_test (fun _ -> ()) test in
   process_results results
 
-(* run list of OUnit test cases, log results *)
-let run_tests ml_fn tests =
+let open_log_out_ch ml_fn =
   let log_fn = ml_fn ^ ".log" in
-  let out_ch = open_out log_fn in
+  open_out log_fn
+
+(* run list of OUnit test cases, log results *)
+let run_tests ml_fn out_ch tests =
   let cprintf s = cfprintf out_ch s in
   let ceprintf s = cfprintf stderr s in
   let logit = logger out_ch in
diff --git a/test-suite/unit-tests/src/utest.mli b/test-suite/unit-tests/src/utest.mli
index 70928228bf..2e0f26e96b 100644
--- a/test-suite/unit-tests/src/utest.mli
+++ b/test-suite/unit-tests/src/utest.mli
@@ -9,4 +9,10 @@ val mk_bool_test : string -> string -> bool -> OUnit.test
 (* the string argument should be the name of the .ml file
    containing the tests; use __FILE__ for that purpose.
  *)
-val run_tests : string -> OUnit.test list -> unit
+val run_tests : string -> out_channel -> OUnit.test list -> unit
+
+(** open output channel for the test log file *)
+(* the string argument should be the name of the .ml file
+   containing the tests; use __FILE__ for that purpose.
+ *)
+val open_log_out_ch : string -> out_channel