Merge pull request #7 from PTB-PSt1/resolve_read_from_empty_buffer

Resolve read from empty buffer

test_buffer/test_buffer.py

@@ -182,6 +182,7 @@ def test_show_all():
     # check if newest elements are received and order is as expected
     assert np.all(result == data)
 
+
 def test_return_format_list():
     M = 4
     tsb = TimeSeriesBuffer(maxlen=maxlen, return_type="list")
@@ -247,3 +248,45 @@ def test_return_format_uarrays():
     assert isinstance(v, np.ndarray)
     assert isinstance(t[0], uncertainties.core.Variable)
     assert isinstance(v[0], uncertainties.core.Variable)
+
+
+def test_pop_empty_array():
+    tsb = TimeSeriesBuffer(maxlen=maxlen, return_type="array")
+    result = tsb.pop()
+
+    assert isinstance(result, np.ndarray)
+    assert result.shape == (0, 4)
+    assert result.size == 0
+
+
+def test_pop_empty_arrays():
+    tsb = TimeSeriesBuffer(maxlen=maxlen, return_type="arrays")
+    t, ut, v, uv = tsb.show(n_samples=n_samples)
+
+    assert isinstance(t, np.ndarray)
+    assert isinstance(ut, np.ndarray)
+    assert isinstance(v, np.ndarray)
+    assert isinstance(uv, np.ndarray)
+    assert t.size == 0
+    assert ut.size == 0
+    assert v.size == 0
+    assert uv.size == 0
+
+
+def test_pop_empty_uarray():
+    tsb = TimeSeriesBuffer(maxlen=maxlen, return_type="uarray")
+    result = tsb.show(n_samples=n_samples)
+
+    assert isinstance(result, np.ndarray)
+    assert result.shape == (0, 2)
+    assert result.size == 0
+
+
+def test_pop_empty_uarrays():
+    tsb = TimeSeriesBuffer(maxlen=maxlen, return_type="uarrays")
+    t, v = tsb.show(n_samples=n_samples)
+
+    assert isinstance(t, np.ndarray)
+    assert isinstance(v, np.ndarray)
+    assert t.size == 0
+    assert v.size == 0

time_series_buffer/__init__.py

@@ -1,3 +1,3 @@
 from .buffer import TimeSeriesBuffer
 
-__version__ = "v0.1.2-beta"
+__version__ = "v0.1.3-beta"

time_series_buffer/buffer.py

@@ -229,14 +229,24 @@ def _return_converter(self, samples):
             return samples
 
         else:
-            data = np.array(samples)
-            t = data[:, 0]
-            ut = data[:, 1]
-            v = data[:, 2]
-            uv = data[:, 3]
+            # handle empty buffer
+            if len(samples) == 0:
+                data = np.empty((0, 4))
+                t = np.empty((0))
+                ut = np.empty((0))
+                v = np.empty((0))
+                uv = np.empty((0))
+
+            # handle non empty buffer
+            else:
+                data = np.array(samples)
+                t = data[:, 0]
+                ut = data[:, 1]
+                v = data[:, 2]
+                uv = data[:, 3]
 
             if self.return_type == "array":
-                return np.vstack(data)
+                return data
 
             elif self.return_type == "arrays":
                 return t, ut, v, uv