Use ``uri`` property

Move workdir to avoid charm build error in gate test.  Move built
artifact back so CI can inspect it. (The layer build-only job in
CI should get an update to cope with this itself)

Change-Id: Icee40b83e6924a6adc9ee1f97eff04522121d5fa
Closes-Bug: #1823729

templates/parts/section-database

@@ -1,5 +1,5 @@
 {% if shared_db.host -%}
 [database]
 
-connection = {{ shared_db.type }}://{{ shared_db.username }}:{{ shared_db.password }}@{{ shared_db.host }}/{{ shared_db.database }}{% if database_ssl_ca %}?ssl_ca={{ database_ssl_ca }}{% if database_ssl_cert %}&ssl_cert={{ database_ssl_cert }}&ssl_key={{ database_ssl_key }}{% endif %}{% endif %}
+connection = {{ shared_db.uri }}
 {% endif -%}

tox.ini

@@ -1,24 +1,32 @@
 [tox]
 skipsdist = True
 envlist = pep8
+toxworkdir = /tmp/tox
 
 [testenv]
 basepython = python2.7
 setenv = VIRTUAL_ENV={envdir}
          PYTHONHASHSEED=0
          TERM=linux
-         JUJU_REPOSITORY={toxinidir}/build
+         JUJU_REPOSITORY={envdir}/tmp/build
 passenv = http_proxy https_proxy
 install_command =
   pip install {opts} {packages}
 deps =
   -r{toxinidir}/requirements.txt
-whitelist_externals = /bin/true /bin/echo
+whitelist_externals = /bin/true /bin/echo /bin/mkdir /bin/ln
 
 [testenv:build]
+# ``charm build`` refuses to output to a subdirectory to the source tree
+# The gate check will look for and validate the built artifacts in the source
+# tree.
+# Build the artifats under /tmp and link back to source directory to alleviate.
 commands =
   /bin/echo 'WARNING: *build* target is for testing only.'
-  charm-build --log-level DEBUG -o {toxinidir}/build .
+  /bin/mkdir -p {envdir}/tmp
+  charm-build --log-level DEBUG -o {envdir}/tmp/build .
+  /bin/ln -s {envdir}/tmp/build/builds {envdir}/tmp/build/trusty
+  /bin/ln -s {envdir}/tmp/build {toxinidir}/build
 
 [testenv:venv]
 basepython = python3