ci(kitchen+travis): modify matrix to include develop platform

* Use balanced matrix based on `template-formula` guidelines
* Initial ref: saltstack-formulas/template-formula#118

.travis.yml

@@ -26,19 +26,24 @@ services:
 #       Ref: https://github.com/saltstack-formulas/template-formula/issues/121
 env:
   matrix:
-    - INSTANCE: default-debian-9-2019-2-py3
-    # - INSTANCE: default-ubuntu-1804-2019-2-py3
+    - INSTANCE: default-debian-9-develop-py3
+    # - INSTANCE: default-ubuntu-1804-develop-py3
+    # - INSTANCE: default-centos-7-develop-py3
+    # - INSTANCE: default-fedora-29-develop-py3
+    # - INSTANCE: default-opensuse-leap-15-develop-py3
+    # - INSTANCE: default-debian-9-2019-2-py3
+    - INSTANCE: default-ubuntu-1804-2019-2-py3
     - INSTANCE: default-centos-7-2019-2-py3
     # - INSTANCE: default-fedora-29-2019-2-py3
-    - INSTANCE: default-opensuse-leap-15-2019-2-py3
+    # - INSTANCE: default-opensuse-leap-15-2019-2-py3
     # - INSTANCE: default-debian-9-2018-3-py2
-    - INSTANCE: default-ubuntu-1604-2018-3-py2
+    # - INSTANCE: default-ubuntu-1604-2018-3-py2
     # - INSTANCE: default-centos-7-2018-3-py2
     - INSTANCE: default-fedora-29-2018-3-py2
     # TODO: Use this when fixed instead of `opensuse-leap-42`
     # Ref: https://github.com/netmanagers/salt-image-builder/issues/2
     # - INSTANCE: default-opensuse-leap-15-2018-3-py2
-    # - INSTANCE: default-opensuse-leap-42-2018-3-py2
+    - INSTANCE: default-opensuse-leap-42-2018-3-py2
     # - INSTANCE: default-debian-8-2017-7-py2
     # - INSTANCE: default-ubuntu-1604-2017-7-py2
     # TODO: Enable after improving the formula to work with other than `systemd`

kitchen.yml

@@ -11,6 +11,39 @@ driver:
 # Make sure the platforms listed below match up with
 # the `env.matrix` instances defined in `.travis.yml`
 platforms:
+  ## SALT `develop`
+  - name: debian-9-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:debian-9
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: ubuntu-1804-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:ubuntu-18.04
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: centos-7-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:centos-7
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: fedora-29-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:fedora-29
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+  - name: opensuse-leap-15-develop-py3
+    driver:
+      image: netmanagers/salt-develop-py3:opensuse-leap-15
+      provision_command:
+        - curl -o bootstrap-salt.sh -L https://bootstrap.saltstack.com
+        - sh bootstrap-salt.sh -XdPbfrq -x python3 git develop
+      run_command: /usr/lib/systemd/systemd
+
   ## SALT 2019.2
   - name: debian-9-2019-2-py3
     driver: