Change local_path to save_path in get_bsrn (#1282)

* Change local_path to save_path

* Update test_bsrn.py

* Update save_path description

* Fix spelling mistake

* Test that file downloaded with save_path is read correctly

* Update save_path description

* Save testfile in temporary directory

Author: AdamRJensen

pvlib/iotools/bsrn.py

@@ -62,7 +62,7 @@ def _empty_dataframe_from_logical_records(logical_records):
 
 
 def get_bsrn(station, start, end, username, password,
-             logical_records=('0100',), local_path=None):
+             logical_records=('0100',), save_path=None):
     """
     Retrieve ground measured irradiance data from the BSRN FTP server.
 
@@ -87,8 +87,8 @@ def get_bsrn(station, start, end, username, password,
     logical_records: list or tuple, default: ('0100',)
         List of the logical records (LR) to parse. Options include: '0100',
         '0300', and '0500'.
-    local_path: str or path-like, optional
-        If specified, path (abs. or relative) of where to save files
+    save_path: str or path-like, optional
+        If specified, a directory path of where to save each monthly file.
 
     Returns
     -------
@@ -178,10 +178,10 @@ def get_bsrn(station, start, end, username, password,
                 # Check that transfer was successfull
                 if not response.startswith('226 Transfer complete'):
                     raise ftplib.Error(response)
-                # Save file locally if local_path is specified
-                if local_path is not None:
+                # Save file locally if save_path is specified
+                if save_path is not None:
                     # Create local file
-                    with open(os.path.join(local_path, filename), 'wb') as f:
+                    with open(os.path.join(save_path, filename), 'wb') as f:
                         f.write(bio.getbuffer())  # Write local file
                 # Open gzip file and convert to StringIO
                 bio.seek(0)  # reset buffer to start of file

pvlib/tests/iotools/test_bsrn.py

@@ -5,6 +5,7 @@
 import pandas as pd
 import pytest
 import os
+import tempfile
 from pvlib.iotools import read_bsrn, get_bsrn
 from ..conftest import (DATA_DIR, RERUNS, RERUNS_DELAY, assert_index_equal,
                         requires_bsrn_credentials)
@@ -78,20 +79,26 @@ def test_read_bsrn_logical_records_not_found():
 def test_get_bsrn(expected_index, bsrn_credentials):
     # Retrieve irradiance data from the BSRN FTP server
     # the TAM station is chosen due to its small file sizes
+    temp_dir = tempfile.TemporaryDirectory()  # create temporary directory
     username, password = bsrn_credentials
     data, metadata = get_bsrn(
         start=pd.Timestamp(2016, 6, 1),
         end=pd.Timestamp(2016, 6, 29),
         station='tam',
         username=username,
         password=password,
-        local_path='')
+        save_path=temp_dir.name)
     assert_index_equal(expected_index, data.index)
     assert 'ghi' in data.columns
     assert 'dni_std' in data.columns
     assert 'dhi_min' in data.columns
     assert 'lwd_max' in data.columns
     assert 'relative_humidity' in data.columns
+    # test that a local file was saved and is read correctly
+    data2, metadata2 = read_bsrn(os.path.join(temp_dir.name, 'tam0616.dat.gz'))
+    assert_index_equal(expected_index, data2.index)
+    assert 'ghi' in data2.columns
+    temp_dir.cleanup()  # explicitly remove temporary directory
 
 
 @requires_bsrn_credentials