BLD: support 3.8 pre

closes pandas-dev#26626

Author: jreback

.travis.yml

@@ -48,11 +48,19 @@ matrix:
       env:
         - JOB="3.6, slow" ENV_FILE="ci/deps/travis-36-slow.yaml" PATTERN="slow"
 
+    - dist: trusty
+      env:
+        - JOB="3.8" ENV_FILE="ci/deps/travis-38.yaml"
+
     allow_failures:
       - dist: trusty
         env:
           - JOB="3.6, slow" ENV_FILE="ci/deps/travis-36-slow.yaml" PATTERN="slow"
 
+      - dist: trusty
+        env:
+          - JOB="3.8" ENV_FILE="ci/deps/travis-38.yaml"
+
 before_install:
   - echo "before_install"
   # set non-blocking IO on travis
@@ -95,5 +103,5 @@ script:
 after_script:
   - echo "after_script start"
   - source activate pandas-dev && pushd /tmp && python -c "import pandas; pandas.show_versions();" && popd
-  - ci/print_skipped.py 
+  - ci/print_skipped.py
   - echo "after_script done"

ci/deps/travis-38.yaml

@@ -0,0 +1,20 @@
+name: pandas-dev
+channels:
+   - conda-forge/label/pre-3.8
+dependencies:
+  - python=3.8.*
+  - pip
+  - pip:
+    - "--pre"
+    - "--no-binary :all:"
+    - cython
+    - git+https://github.com/numpy/numpy
+    - python-dateutil
+    - pytz
+
+    # universal
+    - pytest
+    - pytest-xdist
+    - pytest-mock
+    - moto
+    - hypothesis