Raise if no parameters provided to retrieve_sam() (#770)

Instead of showing up a dialog.

Author: Peque

docs/sphinx/source/whatsnew/v0.7.0.rst

@@ -10,6 +10,11 @@ compatibility notes.
 **Python 2.7 support ended on June 1, 2019.** (:issue:`501`)
 **Minimum numpy version is now 1.10.4. Minimum pandas version is now 0.18.1.**
 
+API Changes
+~~~~~~~~~~~
+* Calling :py:func:`pvlib.pvsystem.retrieve_sam` with no parameters will raise
+  an exception instead of showing up a dialog.
+
 Enhancements
 ~~~~~~~~~~~~
 * Created two new incidence angle modifier functions: :py:func:`pvlib.pvsystem.iam_martin_ruiz`
@@ -38,3 +43,4 @@ Contributors
 * Oscar Dowson (:ghuser:`odow`)
 * Anton Driesse (:ghuser:`adriesse`)
 * Alexander Morgan (:ghuser:`alexandermorgan`)
+* Miguel Sánchez de León Peque (:ghuser:`Peque`)

pvlib/pvsystem.py

@@ -1717,16 +1717,18 @@ def retrieve_sam(name=None, path=None):
     path : None or string, default None
         Path to the SAM file. May also be a URL.
 
-    If both name and path are None, a dialogue will open allowing the
-    user to select a file.
-
     Returns
     -------
     samfile : DataFrame
         A DataFrame containing all the elements of the desired database.
         Each column represents a module or inverter, and a specific
         dataset can be retrieved by the command
 
+    Raises
+    ------
+    ValueError
+        If no name or path is provided.
+
     Notes
     -----
     Files available at https://sam.nrel.gov/sites/default/files/
@@ -1781,11 +1783,7 @@ def retrieve_sam(name=None, path=None):
         else:
             csvdata = path
     elif name is None and path is None:
-        import tkinter
-        from tkinter.filedialog import askopenfilename
-
-        tkinter.Tk().withdraw()
-        csvdata = askopenfilename()
+        raise ValueError("A name or path must be provided!")
 
     return _parse_raw_sam_df(csvdata)
 

pvlib/test/test_pvsystem.py

@@ -274,6 +274,15 @@ def pvsyst_module_params():
     return module_parameters
 
 
+def test_retrieve_sam_raise_no_parameters():
+    """
+    Raise an exception if no parameters are provided to `retrieve_sam()`.
+    """
+    with pytest.raises(ValueError) as error:
+        pvsystem.retrieve_sam()
+    assert 'A name or path must be provided!' == str(error.value)
+
+
 def test_sapm(sapm_module_params):
 
     times = pd.date_range(start='2015-01-01', periods=5, freq='12H')