From 6c938d3b67ff7658d81ba0c90f12aa259ce97654 Mon Sep 17 00:00:00 2001
From: Derrick Chambers <d-chambers@users.noreply.github.com>
Date: Sat, 26 Aug 2023 18:45:19 -0600
Subject: [PATCH] fix_229 (#234)

---
 dascore/core/coords.py         | 17 +++++++++++++++--
 dascore/examples.py            |  9 +--------
 tests/test_core/test_coords.py | 11 +++++++++++
 tests/test_examples.py         |  5 +++++
 4 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/dascore/core/coords.py b/dascore/core/coords.py
index d120013a..c720fc86 100644
--- a/dascore/core/coords.py
+++ b/dascore/core/coords.py
@@ -1024,6 +1024,18 @@ def _check_inputs(data, start, stop, step):
                 msg = "When data is not defined, start, stop, and step must be."
                 raise CoordError(msg)
 
+    def _get_new_max(data, min, step):
+        """Get the new length to use"""
+
+        # for int based data types we need to modify the end time
+        # otherwise this will just go nuts
+        dtype = getattr(min, "dtype", None)
+        if dtype_time_like(dtype) or np.issubdtype(dtype, np.integer):
+            max = min + (len(data) - 1) * step
+        else:
+            max = data[-1]
+        return max
+
     def _maybe_get_start_stop_step(data):
         """Get start, stop, step, is_monotonic."""
         data = np.array(data)
@@ -1036,9 +1048,10 @@ def _maybe_get_start_stop_step(data):
             unique_diff = np.unique(diffs)
             if len(unique_diff) == 1 or all_diffs_close_enough(unique_diff):
                 _min = data[0]
-                _max = data[-1]
                 # this is a poor man's median that preserves dtype
-                _step = np.sort(diffs)[len(diffs) // 2]
+                sorted_diffs = np.sort(diffs)
+                _step = sorted_diffs[len(sorted_diffs) // 2]
+                _max = _get_new_max(data, _min, _step)
                 return _min, _max + _step, _step, is_monotonic
         return None, None, None, is_monotonic
 
diff --git a/dascore/examples.py b/dascore/examples.py
index b9f19710..db541201 100644
--- a/dascore/examples.py
+++ b/dascore/examples.py
@@ -15,7 +15,7 @@
 from dascore.utils.downloader import fetch
 from dascore.utils.misc import register_func
 from dascore.utils.patch import get_default_patch_name
-from dascore.utils.time import to_datetime64, to_timedelta64
+from dascore.utils.time import to_timedelta64
 
 EXAMPLE_PATCHES = {}
 EXAMPLE_SPOOLS = {}
@@ -139,13 +139,6 @@ def _sin_wave_patch(
         data=data,
         coords={"time": time, "distance": distance},
         dims=("time", "distance"),
-        attrs={
-            "time_min": to_datetime64(time_min),
-            "time_step": 1 / sample_rate,
-            "distance_min": 1,
-            "distance_step": 1,
-            "distance_max": 3,
-        },
     )
     return patch
 
diff --git a/tests/test_core/test_coords.py b/tests/test_core/test_coords.py
index 1a9d800b..95b60a16 100644
--- a/tests/test_core/test_coords.py
+++ b/tests/test_core/test_coords.py
@@ -285,6 +285,7 @@ def test_convert_offset_units(self):
         f_array = array * (9 / 5) + 32.0
         coord = get_coord(values=array, units="degC")
         out = coord.convert_units("degF")
+        assert out.shape == f_array.shape
         assert np.allclose(f_array, out.values)
 
     def test_unit_str(self, evenly_sampled_coord):
@@ -820,6 +821,16 @@ def test_arrange_equiv(self):
         coord = get_coord(start=start, stop=stop, step=step)
         assert coord.shape == ar.shape
 
+    def test_unchanged_len(self):
+        """Ensure an array converted to Coord range has same len. See #229."""
+        t_array = np.linspace(0.0, 1, 44100)
+        t_coord = get_coord(values=t_array)
+        assert t_array.shape == t_coord.shape
+        # now test datetime
+        time = dc.to_timedelta64(t_array) + np.datetime64("2020-01-01")
+        time_coord = get_coord(values=time)
+        assert len(time) == len(time_coord)
+
 
 class TestMonotonicCoord:
     """Tests for monotonic array coords."""
diff --git a/tests/test_examples.py b/tests/test_examples.py
index 39eb7ef5..51de49c1 100644
--- a/tests/test_examples.py
+++ b/tests/test_examples.py
@@ -25,6 +25,11 @@ def test_example_1(self):
         out = dc.get_example_patch("example_event_1")
         assert isinstance(out, dc.Patch)
 
+    def test_sin_wav(self):
+        """Ensure the sin wave example can be loaded. See issee 229."""
+        out = dc.get_example_patch("sin_wav")
+        assert isinstance(out, dc.Patch)
+
 
 class TestGetExampleSpool:
     """Test suite for `get_example_spool`."""