Hackage tarball is missing most files in `test/`

The tarball published on Hackage is missing all files in test/ but test/Spec.hs.
...
Preprocessing test suite 'hcoord-test' for hcoord-1.0.0.0..
Building test suite 'hcoord-test' for hcoord-1.0.0.0..
[1 of 1] Compiling Main             ( test/Spec.hs, dist/build/hcoord-test/hcoord-test-tmp/Main.o )

test/Spec.hs:3:1: error:
    Could not find module ‘DMS.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
3 | import DMS.Tests (dmsTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:4:1: error:
    Could not find module ‘ECEFRef.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
4 | import ECEFRef.Tests (ecefrefTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:5:1: error:
    Could not find module ‘IrishRef.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
5 | import IrishRef.Tests (irishrefTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:6:1: error:
    Could not find module ‘LatLng.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
6 | import LatLng.Tests (latlngTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:7:1: error:
    Could not find module ‘MGRSRef.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
7 | import MGRSRef.Tests (mgrsrefTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:8:1: error:
    Could not find module ‘OSRef.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
8 | import OSRef.Tests (osrefTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/Spec.hs:9:1: error:
    Could not find module ‘UTMRef.Tests’
    Use -v (or `:set -v` in ghci) to see a list of the files searched for.
  |
9 | import UTMRef.Tests (utmrefTests)
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
danfran / hcoord

Hackage tarball is missing most files in `test/` #9
