diff --git a/src/srx_caproto_iocs/base.py b/src/srx_caproto_iocs/base.py
index 2ad314f..9fb1faf 100644
--- a/src/srx_caproto_iocs/base.py
+++ b/src/srx_caproto_iocs/base.py
@@ -39,14 +39,14 @@ class CaprotoSaveIOC(PVGroup):
         value="/tmp",
         doc="The directory to write data to. It support datetime formatting, e.g. '/tmp/det/%Y/%m/%d/'",
         string_encoding="utf-8",
-        report_as_string=True,
+        dtype=ChannelType.CHAR,
         max_length=255,
     )
     file_name = pvproperty(
         value="test.h5",
         doc="The file name of the file to write to. It support <str>.format() based formatting, e.g. 'scan_{num:06d}.h5'",
         string_encoding="utf-8",
-        report_as_string=True,
+        dtype=ChannelType.CHAR,
         max_length=255,
     )
     full_file_path = pvproperty(
diff --git a/tests/test_base_ophyd.py b/tests/test_base_ophyd.py
index f5ecade..d052bb1 100644
--- a/tests/test_base_ophyd.py
+++ b/tests/test_base_ophyd.py
@@ -22,7 +22,12 @@ def test_base_ophyd_templates(
     date = now(as_object=True)
     write_dir_root = Path(tmpdirname)
     dir_template = f"{write_dir_root}/{date_template}"
-    write_dir = Path(date.strftime(dir_template))
+
+    # We pre-create the test directory in advance as the IOC is not supposed to create one.
+    # The assumption for the IOC is that the directory will exist before saving a file to that.
+    # We need to replace the blank spaces below for it to work, as the IOC will replace
+    # any blank spaces in `full_file_path` before returning the value.
+    write_dir = Path(date.strftime(dir_template).replace(" ", "_"))
     write_dir.mkdir(parents=True, exist_ok=True)
 
     file_template = "scan_{num:06d}_{uid}.hdf5"