Use input key rather than external input file

Overlap/Tests/Input/global_NSO_in.txt

-&MAIN_NML max_delta = 3 /
-/
-/

Overlap/Tests/Input/non_successive_overlap_in.txt

-&MAIN_NML max_delta = 3, k_test_2 = 0 /
-/
-/

Overlap/Tests/Input/region_1_get_snapshot_nml.txt

-&MAIN_NML CORNER = 5.125, -36.375, NLON = 29, NLAT = 17 /

Overlap/Tests/Input/region_1_get_snapshot_recv_nml.txt

-&MAIN_NML CORNER = 5.125, -36.375, NLON = 29, NLAT = 17, k = 2 /

Overlap/Tests/short_tests.json

@@ -118,7 +118,7 @@
         ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/non_successive_overlap_in.txt",
+        "input": "&MAIN_NML max_delta = 3, k_test_2 = 0 /\n/\n/\n",
         "description": "Overlap of a snapshot with itself. Same as Successive_overlap, except for max_delta.",
         "title": "Non_successive_overlap",
         "command":
@@ -128,7 +128,7 @@
         ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/global_NSO_in.txt",
+        "input": "&MAIN_NML max_delta = 3 /\n/\n/\n",
         "description":
 	"Overlap of different snapshots. Same as Successive_overlap_different_snapshots, except for max_delta.",
         "title": "NSO_different_snapshots",
@@ -139,7 +139,7 @@
             ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/global_NSO_in.txt",
+        "input": "&MAIN_NML max_delta = 3 /\n/\n/\n",
         "description":
 	"Same as Successive_overlap_region_5, except for max_delta.",
         "title": "NSO_region_5",
@@ -150,7 +150,7 @@
             ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/global_NSO_in.txt",
+        "input": "&MAIN_NML max_delta = 3 /\n/\n/\n",
         "description":
 	"Same as Successive_overlap_global, except for max_delta.",
         "title": "NSO_global",
@@ -190,7 +190,8 @@
         ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/region_1_get_snapshot_nml.txt",
+        "input":
+	"&MAIN_NML CORNER = 5.125, -36.375, NLON = 29, NLAT = 17 /\n",
         "title": "Get_dispatch_snap",
         "stdout": "test_get_dispatch_snap_stdout.txt",
         "commands": [
@@ -208,7 +209,7 @@
         ]
     },
     {
-        "stdin_filename": "$src_dir/Overlap/Tests/Input/region_1_get_snapshot_recv_nml.txt",
+        "input": "&MAIN_NML CORNER = 5.125, -36.375, NLON = 29, NLAT = 17, k = 2 /\n",
         "description": "Receive case for one of the processes in procedure get_snapshot.",
         "title": "Get_dispatch_snap_recv",
         "stdout": "test_get_dispatch_snap_stdout.txt",