Remove os cleanup, add read from db file

Author: Andrew Yang

src/diffpy/utils/parsers/__init__.py

@@ -17,7 +17,7 @@
 """
 
 from .loaddata import loadData
-from .loadmetafile import load_PDF_into_db, markup_PDF, apply_schema_to_file, markup_oneline
+from .loadmetafile import load_PDF_into_db, load_from_db, markup_PDF, apply_schema_to_file, markup_oneline
 from .resample import resample
 
 # silence the pyflakes syntax checker

src/diffpy/utils/parsers/loadmetafile.py

@@ -80,6 +80,27 @@ def load_PDF_into_db(dbname, pdfname, hddata: dict, rv: list, show_path=True):
     return pdfs
 
 
+def load_from_db(filename):
+    """Load a dictionary from a database file.
+
+    filename    -- database file to load from.
+
+    Returns a dictionary of database information.
+    """
+
+    # check if supported type
+    extension = pathlib.Path(filename).suffix
+    if extension not in supported_formats:
+        raise Exception(f"Format of {filename} is not supported.")
+
+    # json
+    if extension == '.json':
+        with open(filename, 'r') as json_file:
+            j_dict = json.load(json_file)
+
+    return j_dict
+
+
 def markup_PDF(hddata: dict, rv: list, muname=None):
     # FIXME: may be better suited for REST API package, not diffpy.utils
     """Put PDF file information into a dictionary.

src/diffpy/utils/tests/test_loadmetafile.py

@@ -1,4 +1,4 @@
-from diffpy.utils.parsers import load_PDF_into_db, markup_PDF, apply_schema_to_file, markup_oneline
+from diffpy.utils.parsers import load_PDF_into_db, load_from_db, markup_PDF, apply_schema_to_file, markup_oneline
 from diffpy.utils.parsers import loadData
 from diffpy.utils.tests.testhelpers import datafile
 
@@ -30,9 +30,8 @@ def test_load_gr(tmp_path):
     # compare to target
     # first compare if base data is same
     import json
-    with open(targetjson, 'r') as target:
-        target_db_data = json.load(target)
-        assert target_db_data == db_data
+    target_db_data = load_from_db(targetjson)
+    assert target_db_data == db_data
     # then compare file structure/organization
     assert filecmp.cmp(generatedjson, targetjson)
 
@@ -48,12 +47,7 @@ def test_markup_gr(tmp_path):
 
     # check against target
     # first compare data is same
-    import json
-    with open(targetmu, 'r') as target:
-        target_data = json.load(target)
-        assert target_data == data
+    target_data = load_from_db(targetmu)
+    assert target_data == data
     # then compare structure
     assert filecmp.cmp(generatedmu, targetmu)
-
-    # cleanup
-    os.remove(generatedmu)