Update test matrix removing Python 3.4 and adding 3.6, 3.7, 3.8

Python 3.4 is now EOL.

Update to Xenial required for Python 3.7 and 3.8 on Travis.

Update flake8 to use Python 3.8 compatible pyflakes [1]. Allow the
latest matching pycodestyle to be automatically installed.

Use libsqlite3-mod-spatialite to save compile time.

[1] PyCQA/pyflakes#367

.travis.yml

@@ -1,13 +1,13 @@
 language: python
 
 sudo: true
-dist: trusty
+dist: xenial
 
 addons:
-  postgresql: 9.3
+  postgresql: 9.6
   apt:
     packages:
-      - postgresql-9.3-postgis-2.3
+      - postgresql-9.6-postgis-2.4
       - python2.7-dev
       - python3-dev
       - autotools-dev
@@ -17,6 +17,7 @@ addons:
       - libproj-dev
       - libreadline-dev
       - libsqlite3-dev
+      - libsqlite3-mod-spatialite
       - libxml2-dev
       - zlib1g-dev
 
@@ -27,33 +28,32 @@ notifications:
 services:
   - postgresql
 
-cache:
-  directories:
-    - libspatialite-4.3.0a
-
 matrix:
   include:
     - python: 2.7
       env:
       - TOX_ENV=py27sqla11
-    - python: 3.4
-      env:
-      - TOX_ENV=py34sqla11
     - python: 3.5
       env:
       - TOX_ENV=py35sqla11
-    - python: pypy
+    - python: 3.6
+      env:
+      - TOX_ENV=py36sqla11
+    - python: 3.7
+      env:
+      - TOX_ENV=py37sqla11
+    - python: 3.8
+      env:
+      - TOX_ENV=py38sqla11
+    - python: pypy3
       env:
       - TOX_ENV=pypysqla11
 
 env:
   global:
-    - SPATIALITE_LIBRARY_PATH="/usr/local/lib/mod_spatialite.so"
+    - SPATIALITE_LIBRARY_PATH="/usr/lib/x86_64-linux-gnu/mod_spatialite.so"
 
 install:
-  # Install Spatialite
-  - ./install-spatialite.sh
-
   # Install tox
   - pip install tox
 
@@ -81,7 +81,7 @@ before_script:
 
 script:
   # Run the library through flake8
-  - flake8 geoalchemy2 tests --ignore=E711 --ignore=W503
+  - flake8 geoalchemy2 tests --ignore=W503 --ignore=W504
 
   # Run the unit test suite
   - tox -e $TOX_ENV --sitepackages -- -v --cov geoalchemy2 --cov-report term-missing

requirements.txt

@@ -2,8 +2,7 @@
 -e .
 
 # Additional requirements for running the testsuite and development
-pycodestyle==2.2.0
-flake8==3.2.0
+flake8==3.7.9
 pytest==3.7.4
 pytest-cov==2.5.1
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist=py27sqla11, py34sqla11, py35sqla11, pypysqla11
+envlist=py27sqla11, py35sqla11, py36sqla11, py37sqla11, py38sqla11, pypysqla11
 
 [testenv]
 passenv=SPATIALITE_LIBRARY_PATH
@@ -15,23 +15,37 @@ deps=
     pysqlite
     -rrequirements.txt
 
-[testenv:py34sqla11]
-basepython=python3.4
+[testenv:py35sqla11]
+basepython=python3.5
 deps=
     SQLAlchemy==1.1.2
     psycopg2
     -rrequirements.txt
 
-[testenv:py35sqla11]
-basepython=python3.5
+[testenv:py36sqla11]
+basepython=python3.6
 deps=
     SQLAlchemy==1.1.2
     psycopg2
     -rrequirements.txt
 
-[testenv:pypysqla11]
-basepython=pypy
+[testenv:py37sqla11]
+basepython=python3.7
 deps=
     SQLAlchemy==1.1.2
+    psycopg2
+    -rrequirements.txt
+
+[testenv:py38sqla11]
+basepython=python3.8
+deps=
+    SQLAlchemy==1.1.2
+    psycopg2
+    -rrequirements.txt
+
+[testenv:pypysqla11]
+basepython=pypy3
+deps=
+    SQLAlchemy==1.3.15
     psycopg2cffi
     -rrequirements.txt