diff --git a/src/tests/jf_test_15.F90 b/src/tests/jf_test_15.F90
index e53986c71..d1991f946 100644
--- a/src/tests/jf_test_15.F90
+++ b/src/tests/jf_test_15.F90
@@ -216,7 +216,9 @@ subroutine test_15(error_cnt)
 
         !****************************************
 
-        file1 = json_file(p2,json)  !constructor
+        !file1 = json_file(p2,json)  ! memory leak with gfortran?
+        call file1%initialize(json)
+        call file1%add(p2); nullify(p2)
         call file1%destroy(destroy_core=.true.)
 
         !****************************************
diff --git a/src/tests/jf_test_25.F90 b/src/tests/jf_test_25.F90
index 332ae7e4c..468542e86 100644
--- a/src/tests/jf_test_25.F90
+++ b/src/tests/jf_test_25.F90
@@ -108,7 +108,9 @@ subroutine test_25(error_cnt)
 #endif
 
     ! test json_file interface
-    f = json_file(p)
+    !f = json_file(p) ! memory leak in gfortran?
+    call f%initialize()
+    call f%add(p)
     nullify(p) ! data is now in f
     call f%get('str_array', vec, ilen, found)
     if (.not. found) then
diff --git a/src/tests/jf_test_27.F90 b/src/tests/jf_test_27.F90
index 017ce0ece..d612ba3d9 100644
--- a/src/tests/jf_test_27.F90
+++ b/src/tests/jf_test_27.F90
@@ -60,7 +60,9 @@ subroutine test_27(error_cnt)
     call json%print(p,int(output_unit,IK))
 
     ! test json_file interface
-    f = json_file(p)
+    !f = json_file(p) ! memory leak in gfortran?
+    call f%initialize()
+    call f%add(p)
     nullify(p) ! data is now in f
     call f%initialize(compress_vectors=.true.)
     call f%print()
diff --git a/src/tests/jf_test_37.F90 b/src/tests/jf_test_37.F90
index eaa1ffd1d..a47fa7e54 100644
--- a/src/tests/jf_test_37.F90
+++ b/src/tests/jf_test_37.F90
@@ -39,26 +39,34 @@ subroutine test_37(error_cnt)
     call json%initialize(no_whitespace=.true.)
 
     call json%deserialize(p, CK_'{"a": ["1", "2", "3"]}')
-    f = json_file(p,no_whitespace=.true.)
+    !f = json_file(p,no_whitespace=.true.) ! memory leak in gfortran?
+    call f%initialize(no_whitespace=.true.)
+    call f%add(p)
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
     call json%deserialize(p, CK_'{"b": ["4", "5", "6"]}')
-    f = json_file(p,json)
+    !f = json_file(p,json) ! memory leak in gfortran?
+    call f%initialize(json)
+    call f%add(p)
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
-    f = json_file(CK_'{"x": [1,2,3]}',no_whitespace=.true.)
+    !f = json_file(CK_'{"x": [1,2,3]}',no_whitespace=.true.) ! memory leak in gfortran?
+    call f%initialize(no_whitespace=.true.)
+    call f%deserialize(CK_'{"x": [1,2,3]}')
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
-    f = json_file(CK_'{"y": [4,5,6]}',json)
+    !f = json_file(CK_'{"y": [4,5,6]}',json) ! memory leak in gfortran?
+    call f%initialize(json)
+    call f%deserialize(CK_'{"y": [4,5,6]}')
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
@@ -69,26 +77,34 @@ subroutine test_37(error_cnt)
     ! also test default character kind when unicode is enabled:
 
     call json%deserialize(p, CDK_'{"a": ["1", "2", "3"]}')
-    f = json_file(p,no_whitespace=.true.)
+    !f = json_file(p,no_whitespace=.true.) ! memory leak in gfortran?
+    call f%initialize(no_whitespace=.true.)
+    call f%add(p)
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
     call json%deserialize(p, CDK_'{"b": ["4", "5", "6"]}')
-    f = json_file(p,json)
+    !f = json_file(p,json) ! memory leak in gfortran?
+    call f%initialize(json)
+    call f%add(p)
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
-    f = json_file(CDK_'{"x": [1,2,3]}',no_whitespace=.true.)
+    !f = json_file(CDK_'{"x": [1,2,3]}',no_whitespace=.true.) ! memory leak in gfortran?
+    call f%initialize(no_whitespace=.true.)
+    call f%deserialize(CDK_'{"x": [1,2,3]}')
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
     call f%destroy()
 
-    f = json_file(CDK_'{"y": [4,5,6]}',json)
+    !f = json_file(CDK_'{"y": [4,5,6]}',json) ! memory leak in gfortran?
+    call f%initialize(json)
+    call f%deserialize(CDK_'{"y": [4,5,6]}')
     call f%print(int(error_unit,IK))
     write(error_unit,'(A)') ''
     call check_for_error()
diff --git a/src/tests/jf_test_39.F90 b/src/tests/jf_test_39.F90
index a22cfaea9..eeec7cf2a 100644
--- a/src/tests/jf_test_39.F90
+++ b/src/tests/jf_test_39.F90
@@ -44,7 +44,9 @@ subroutine test_39(error_cnt)
 
     do i = 1, size(tests)
 
-        json = json_file(trim(tests(i)),verbose=.true.,stop_on_error=.true.)
+        !json = json_file(trim(tests(i)),verbose=.true.,stop_on_error=.true.)  ! memory leak in gfortran?
+        call json%initialize(verbose=.true.,stop_on_error=.true.)
+        call json%deserialize(trim(tests(i)))
         call json%print(int(error_unit,IK))
         write(error_unit,'(A)') ''
         if (json%failed()) then
diff --git a/src/tests/jf_test_41.F90 b/src/tests/jf_test_41.F90
index 1fd6fc743..8e9cf0c39 100644
--- a/src/tests/jf_test_41.F90
+++ b/src/tests/jf_test_41.F90
@@ -57,7 +57,9 @@ subroutine test_41(error_cnt)
         write(error_unit,'(A)') ''
         write(error_unit,'(A)') 'copying to json_file...'
 
-        f = json_file(p)
+        !f = json_file(p) ! memory leak in gfortran?
+        call f%initialize()
+        call f%add(p)
 
         call f2%add(p2)
         nullify(p2) ! data is now in f
diff --git a/src/tests/jf_test_46.F90 b/src/tests/jf_test_46.F90
index 558cc7f0d..92bca2e86 100644
--- a/src/tests/jf_test_46.F90
+++ b/src/tests/jf_test_46.F90
@@ -166,7 +166,8 @@ subroutine test_46(error_cnt)
     ! now, json_file routines:
     !---------------------------------
 
-    json_f = json_file(str)
+    !json_f = json_file(str)  ! memory leak in gfortran?
+    call json_f%deserialize(str)
 
     ! unicode:
     call json_f%get(CK_'not_there', ival, found, default=99_IK)