ENH: datetime: Tests and fixes for datetime64 <-> object roundtripping

4 files changed, 55 insertions, 28 deletions

diff --git a/numpy/core/src/multiarray/arraytypes.c.src b/numpy/core/src/multiarray/arraytypes.c.src
index 80bd59636..ac3da4558 100644
--- a/numpy/core/src/multiarray/arraytypes.c.src
+++ b/numpy/core/src/multiarray/arraytypes.c.src
@@ -1069,7 +1069,7 @@ DATETIME_getitem(char *ip, PyArrayObject *ap) {
     /* Get the datetime units metadata */
     meta = get_datetime_metadata_from_dtype(PyArray_DESCR(ap));
     if (meta == NULL) {
-        return -1;
+        return NULL;
     }
 
     if ((ap == NULL) || PyArray_ISBEHAVED_RO(ap)) {
diff --git a/numpy/core/src/multiarray/datetime.c b/numpy/core/src/multiarray/datetime.c
index accadf7c5..0d1ed563e 100644
--- a/numpy/core/src/multiarray/datetime.c
+++ b/numpy/core/src/multiarray/datetime.c
@@ -328,7 +328,7 @@ convert_datetimestruct_to_datetime(PyArray_DatetimeMetaData *meta,
     }
     else if (base == NPY_FR_M) {
         /* Truncate to the month */
-        ret = 12 * (dts->year - 1970) + dts->month;
+        ret = 12 * (dts->year - 1970) + (dts->month - 1);
     }
     else {
         /* Otherwise calculate the number of days to start */
@@ -2602,27 +2602,33 @@ convert_datetime_to_pyobject(npy_datetime dt, PyArray_DatetimeMetaData *meta)
 
     /* If the type's precision is greater than microseconds, return an int */
     if (meta->base > NPY_FR_us) {
-        ret = PyLong_FromLongLong(dt);
+        /* Skip use of a tuple for the events, just return the raw int */
+        return PyLong_FromLongLong(dt);
     }
-    else {
-        /* Convert to a datetimestruct */
-        if (convert_datetime_to_datetimestruct(meta, dt, &dts) < 0) {
-            return NULL;
-        }
 
-        /* If the type's precision is greater than days, return a datetime */
-        if (meta->base > NPY_FR_D) {
-            ret = PyDateTime_FromDateAndTime(dts.year, dts.month, dts.day,
-                                    dts.hour, dts.min, dts.sec, dts.us);
-        }
-        /* Otherwise return a date */
-        else {
-            ret = PyDate_FromDate(dts.year, dts.month, dts.day);
-        }
+    /* Convert to a datetimestruct */
+    if (convert_datetime_to_datetimestruct(meta, dt, &dts) < 0) {
+        return NULL;
     }
 
-    if (ret == NULL) {
-        return NULL;
+    /*
+     * If the year is outside the range of years supported by Python's
+     * datetime, or the datetime64 falls on a leap second,
+     * return a raw int.
+     */
+    if (dts.year < 1 || dts.year > 9999 || dts.sec == 60) {
+        /* Also skip use of a tuple for the events */
+        return PyLong_FromLongLong(dt);
+    }
+
+    /* If the type's precision is greater than days, return a datetime */
+    if (meta->base > NPY_FR_D) {
+        ret = PyDateTime_FromDateAndTime(dts.year, dts.month, dts.day,
+                                dts.hour, dts.min, dts.sec, dts.us);
+    }
+    /* Otherwise return a date */
+    else {
+        ret = PyDate_FromDate(dts.year, dts.month, dts.day);
     }
 
     /* If there is one event, just return the datetime */
@@ -2637,6 +2643,7 @@ convert_datetime_to_pyobject(npy_datetime dt, PyArray_DatetimeMetaData *meta)
             return NULL;
         }
         PyTuple_SET_ITEM(tup, 0, ret);
+
         ret = PyInt_FromLong(dts.event);
         if (ret == NULL) {
             Py_DECREF(tup);
diff --git a/numpy/core/src/multiarray/methods.c b/numpy/core/src/multiarray/methods.c
index a4c92b2a1..02a619eec 100644
--- a/numpy/core/src/multiarray/methods.c
+++ b/numpy/core/src/multiarray/methods.c
@@ -185,8 +185,6 @@ array_view(PyArrayObject *self, PyObject *args, PyObject *kwds)
 
     if ((out_dtype) &&
         (PyArray_DescrConverter(out_dtype, &dtype) == PY_FAIL)) {
-        PyErr_SetString(PyExc_ValueError,
-                        "Dtype must be a numpy data-type");
         return NULL;
     }
 
diff --git a/numpy/core/tests/test_datetime.py b/numpy/core/tests/test_datetime.py
index 46fcdc0d9..79f3e9e41 100644
--- a/numpy/core/tests/test_datetime.py
+++ b/numpy/core/tests/test_datetime.py
@@ -96,17 +96,39 @@ class TestDateTime(TestCase):
                             np.dtype('m8[s]'), np.dtype('m8[as]'))
 
 
-    """
-    def test_pyobject_conversion(self):
+    def test_pyobject_roundtrip(self):
         # All datetime types should be able to roundtrip through object
-        a = np.array([-1020040340, -2942398, -1, 0, 1, 234523453, 1199164176],
+        a = np.array([0,0,0,0,0,0,0,0,
+                      -1020040340, -2942398, -1, 0, 1, 234523453, 1199164176],
                                                         dtype=np.int64)
         for unit in ['M8[as]', 'M8[16fs]', 'M8[ps]', 'M8[us]',
-                     'M8[as//12]', 'M8[us//16]', 'M8[D]', 'M8[D]//4',
+                     'M8[as]//12', 'M8[us]//16', 'M8[D]', 'M8[D]//4',
                      'M8[W]', 'M8[M]', 'M8[Y]']:
-            assert_equal(a.view(dtype=unit).astype(object).astype(unit),
-                                                        a.view(dtype=unit))
-    """
+            b = a.copy().view(dtype=unit)
+            b[0] = '-0001-01-01'
+            b[1] = '-0001-12-31'
+            b[2] = '0000-01-01'
+            b[3] = '0001-01-01'
+            b[4] = '1969-12-31T23:59:59.999999Z'
+            b[5] = '1970-01-01'
+            b[6] = '9999-12-31T23:59:59.999999Z'
+            b[7] = '10000-01-01'
+
+            assert_equal(b.astype(object).astype(unit), b,
+                            "Error roundtripping unit %s" % unit)
+
+    def test_month_trucation(self):
+        # Make sure that months are truncating correctly
+        assert_equal(np.array('1945-03-01', dtype='M8[M]'),
+                     np.array('1945-03-31', dtype='M8[M]'))
+        assert_equal(np.array('1969-11-01', dtype='M8[M]'),
+                     np.array('1969-11-30T23:59:59.999999Z', dtype='M8[M]'))
+        assert_equal(np.array('1969-12-01', dtype='M8[M]'),
+                     np.array('1969-12-31T23:59:59.999999Z', dtype='M8[M]'))
+        assert_equal(np.array('1970-01-01', dtype='M8[M]'),
+                     np.array('1970-01-31T23:59:59.999999Z', dtype='M8[M]'))
+        assert_equal(np.array('1980-02-01', dtype='M8[M]'),
+                     np.array('1980-02-29T23:59:59.999999Z', dtype='M8[M]'))
 
     def test_hours(self):
         t = np.ones(3, dtype='M8[s]')