TST: add TestReadPyTablesHDF5 test scaffold

Author: jgehrcke

pandas/tests/io/test_pytables.py

@@ -5,6 +5,7 @@
 from io import BytesIO
 import os
 import tempfile
+import time
 from warnings import catch_warnings, simplefilter
 
 import numpy as np
@@ -5177,3 +5178,86 @@ def test_dst_transitions(self):
                 store.append('df', df)
                 result = store.select('df')
                 assert_frame_equal(result, df)
+
+
+class TestReadPyTablesHDF5(Base):
+    """
+    A group of tests which covers reading HDF5 files written by plain PyTables
+    (not written by pandas).
+    """
+
+    def _create_simple_hdf5_file_with_pytables(self):
+
+        table_schema = {
+            'c0': tables.Time64Col(pos=0),
+            'c1': tables.StringCol(5, pos=1),
+            'c2': tables.UInt32Col(pos=2),
+        }
+
+        t0 = time.time()
+
+        testsamples = [
+            {'c0': t0, 'c1': 'aaaaa', 'c2': 1},
+            {'c0': t0 + 1, 'c1': 'bbbbb', 'c2': 2},
+            {'c0': t0 + 2, 'c1': 'ccccc', 'c2': 10**5},
+            {'c0': t0 + 3, 'c1': 'ddddd', 'c2': 4294967295},
+        ]
+
+        # This returns a path and does not open the file.
+        tmpfilepath = create_tempfile(self.path)
+        objectname = 'pandas_test_timeseries'
+
+        with tables.open_file(tmpfilepath, mode='w') as hf:
+            t = hf.create_table('/', name=objectname, description=table_schema)
+            for sample in testsamples:
+                for key, value in sample.items():
+                    t.row[key] = value
+                t.row.append()
+
+        return tmpfilepath, objectname, testsamples
+
+    def _compare(self, df, samples):
+        """Compare the reference `samples` with the contents in DataFrame `df`.
+        """
+        for idx, row in df.iterrows():
+            # Compare Time64Col values with tolerance.
+            tm.assert_almost_equal(samples[idx]['c0'], row['c0'])
+
+            # Compare a short string.
+            assert samples[idx]['c1'] == row['c1']
+
+            # Compare an unsigned 32 bit integer.
+            assert samples[idx]['c2'] == row['c2']
+
+    def test_read_complete(self):
+        path, objname, samples = self._create_simple_hdf5_file_with_pytables()
+
+        df = pd.read_hdf(path, key=objname)
+        self._compare(df, samples)
+
+    def test_read_with_start(self):
+        path, objname, samples = self._create_simple_hdf5_file_with_pytables()
+
+        # Currently this fails as of
+        # https://github.com/pandas-dev/pandas/issues/11188
+        with pytest.raises(ValueError, match='Shape of passed values is'):
+            df = pd.read_hdf(path, key=objname, start=1)
+            self._compare(df, samples[1:])
+
+    def test_read_with_stop(self):
+        path, objname, samples = self._create_simple_hdf5_file_with_pytables()
+
+        # Currently this fails as of
+        # https://github.com/pandas-dev/pandas/issues/11188
+        with pytest.raises(ValueError, match='Shape of passed values is'):
+            df = pd.read_hdf(path, key=objname, stop=1)
+            self._compare(df, samples[0:1])
+
+    def test_read_with_startstop(self):
+        path, objname, samples = self._create_simple_hdf5_file_with_pytables()
+
+        # Currently this fails as of
+        # https://github.com/pandas-dev/pandas/issues/11188
+        with pytest.raises(ValueError, match='Shape of passed values is'):
+            df = pd.read_hdf(path, key=objname, start=1, stop=2)
+            self._compare(df, samples[1:2])