Improve time conversion helpers

.pre-commit-config.yaml

@@ -8,6 +8,6 @@ repos:
 -   repo: https://github.com/pycqa/isort
     rev: 5.12.0
     hooks:
-      - id: isort
-        name: isort (python)
-        language_version: python3.10
+    - id: isort
+      name: isort (python)
+      language_version: python3.10

cxotime/cxotime.py

@@ -25,13 +25,6 @@
 iers.conf.auto_download = False
 
 
-def print_time_conversions():
-    """Interface to entry_point script ``cxotime`` to print time conversions"""
-    date = None if len(sys.argv) == 1 else sys.argv[1]
-    date = CxoTime(date)
-    date.print_conversions()
-
-
 def date2secs(date):
     """Fast conversion from Year Day-of-Year date(s) to CXC seconds
 
@@ -310,9 +303,9 @@ def now(cls):
 
     now.__doc__ = Time.now.__doc__
 
-    def print_conversions(self):
+    def print_conversions(self, file=sys.stdout):
         """
-        Print a table of conversions to other formats.
+        Print a table of conversions to a standard set of formats.
 
         Example::
 
@@ -326,33 +319,63 @@ def print_conversions(self):
            decimalyear 2010.00000
            iso         2010-01-01 00:00:00.000
            unix        1262304000.000
+
+        :param file: file-like, optional
+            File-like object to write output (default=sys.stdout).
         """
         from astropy.table import Table
-        from dateutil import tz
 
         formats = {
-            "date": "s",
             "cxcsec": ".3f",
             "decimalyear": ".5f",
-            "iso": "s",
             "unix": ".3f",
         }
-        dt_utc = self.datetime.replace(tzinfo=tz.tzutc())
-        dt_local = dt_utc.astimezone(tz.tzlocal())
 
-        rows = []
-        rows.append(["local", dt_local.strftime("%Y %a %b %d %I:%M:%S %p %Z")])
-        rows.append(["iso_local", dt_local.isoformat()])
+        conversions = self.get_conversions()
+
+        # Format numerical values as strings with specified precision
         for name, fmt in formats.items():
-            row = [name, format(getattr(self, name), fmt)]
-            rows.append(row)
+            conversions[name] = format(conversions[name], fmt)
 
-        out = Table(rows=rows, names=["format", "value"])
+        formats = list(conversions)
+        values = list(conversions.values())
+        out = Table([formats, values], names=["format", "value"])
         out["format"].info.format = "<s"
         out["value"].info.format = "<s"
+
         # Remove the header and print
         lines = out.pformat_all()[2:]
-        print("\n".join(lines))
+        print("\n".join(lines), file=file)
+
+    def get_conversions(self):
+        """
+        Get a dict of conversions to a standard set of formats.
+
+        Example::
+
+           >>> from cxotime import CxoTime
+           >>> t = CxoTime('2010:001:00:00:00')
+           >>> t.get_conversions()
+           {'local': '2009 Thu Dec 31 07:00:00 PM EST',
+           'iso_local': '2009-12-31T19:00:00-05:00',
+           'date': '2010:001:00:00:00.000',
+           'cxcsec': 378691266.184,
+           'decimalyear': 2010.0,
+           'iso': '2010-01-01 00:00:00.000',
+           'unix': 1262304000.0}
+        """
+        from datetime import timezone
+
+        out = {}
+
+        dt_local = self.datetime.replace(tzinfo=timezone.utc).astimezone(tz=None)
+        out["local"] = dt_local.strftime("%Y %a %b %d %I:%M:%S %p %Z")
+        out["iso_local"] = dt_local.isoformat()
+
+        for name in ["date", "cxcsec", "decimalyear", "iso", "unix"]:
+            out[name] = getattr(self, name)
+
+        return out
 
 
 class TimeSecs(TimeCxcSec):

cxotime/scripts/print_time_conversions.py

@@ -0,0 +1,34 @@
+# Licensed under a 3-clause BSD style license - see LICENSE.rst
+import sys
+
+from cxotime import CxoTime
+
+
+def main(date=None, file=sys.stdout):
+    """Interface to entry_point script ``cxotime`` to print time conversions.
+
+    :param date: str, float, optional
+        Date for time conversion if sys.argv[1] is not provided. Mostly for testing.
+    :param file: file-like, optional
+        File-like object to write output (default=sys.stdout). Mostly for testing.
+    """
+    if date is None:
+        if len(sys.argv) > 2:
+            print("Usage: cxotime [date]")
+            sys.exit(1)
+
+        if len(sys.argv) == 2:
+            date = sys.argv[1]
+
+    # If the input can be converted to a float then it is a CXC seconds value
+    try:
+        date = float(date)
+    except Exception:
+        pass
+
+    date = CxoTime(date)
+    date.print_conversions(file)
+
+
+if __name__ == "__main__":
+    main()

cxotime/tests/test_cxotime.py

@@ -3,6 +3,7 @@
 Simple test of CxoTime.  The base Time object is extremely well
 tested, so this simply confirms that the add-on in CxoTime works.
 """
+import io
 
 import astropy.units as u
 import numpy as np
@@ -11,6 +12,7 @@
 from Chandra.Time import DateTime
 
 from .. import CxoTime, date2secs, secs2date
+from ..scripts import print_time_conversions
 
 
 def test_cxotime_basic():
@@ -274,3 +276,38 @@ def test_secs2date(date):
     val = secs2date(t_secs)
     assert isinstance(val, np.ndarray)
     assert val.dtype.kind == "U"
+
+
+def test_get_conversions():
+    t = CxoTime("2010:001:00:00:00")
+    out = t.get_conversions()
+    exp = {
+        "local": "2009 Thu Dec 31 07:00:00 PM EST",
+        "iso_local": "2009-12-31T19:00:00-05:00",
+        "date": "2010:001:00:00:00.000",
+        "cxcsec": 378691266.184,
+        "decimalyear": 2010.0,
+        "iso": "2010-01-01 00:00:00.000",
+        "unix": 1262304000.0,
+    }
+    assert out == exp
+
+
+@pytest.mark.parametrize(
+    "date", ["378691266.184", "2010:001", "2010-01-01 00:00:00.000"]
+)
+def test_print_time_conversions(date):
+    out = io.StringIO()
+    print_time_conversions.main(date, file=out)
+    exp = """\
+local       2009 Thu Dec 31 07:00:00 PM EST
+iso_local   2009-12-31T19:00:00-05:00
+date        2010:001:00:00:00.000
+cxcsec      378691266.184
+decimalyear 2010.00000
+iso         2010-01-01 00:00:00.000
+unix        1262304000.000"""
+    out_str = out.getvalue()
+    # Strip all trailing whitespace on each line
+    out_str = "\n".join([line.rstrip() for line in out_str.splitlines()])
+    assert out_str == exp

setup.py

@@ -8,7 +8,7 @@
 
 entry_points = {
     "console_scripts": [
-        "cxotime = cxotime.cxotime:print_time_conversions",
+        "cxotime = cxotime.scripts.print_time_conversions:main",
     ]
 }
 
@@ -20,7 +20,7 @@
     use_scm_version=True,
     setup_requires=["setuptools_scm", "setuptools_scm_git_archive"],
     zip_safe=False,
-    packages=["cxotime", "cxotime.tests"],
+    packages=["cxotime", "cxotime.scripts", "cxotime.tests"],
     tests_require=["pytest"],
     cmdclass=cmdclass,
     entry_points=entry_points,