Automated tests for exceptions

Handle various positive and negative cases. Should handle every error
and warning path when reading exceptions objects or rule exception
fields, and various positive cases of using exceptions to prevent
alerts.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

test/rules/exceptions/rule_exception_values_listref.yaml

@@ -0,0 +1,32 @@
+#
+# Copyright (C) 2020 The Falco Authors.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+- list: cat_cmdlines
+  items: [cat /dev/zero, "cat /dev/null"]
+
+- rule: Open From Cat
+  desc: A process named cat does an open
+  condition: evt.type=open and proc.name=cat
+  output: "An open was seen (command=%proc.cmdline)"
+  exceptions:
+    - name: proc_name_cmdline
+      fields: [proc.name, proc.cmdline]
+      comps: [=, in]
+      values:
+        - [cat, (cat_cmdlines)]
+  priority: WARNING
+