refactor aaparser pkg, add unit tests

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

aaparser/aaparser_test.go

@@ -0,0 +1,65 @@
+package aaparser
+
+import (
+	"testing"
+)
+
+type versionExpected struct {
+	output string
+	major  int
+	minor  int
+}
+
+func TestParseVersion(t *testing.T) {
+	versions := []versionExpected{
+		{
+			output: `AppArmor parser version 2.10
+Copyright (C) 1999-2008 Novell Inc.
+Copyright 2009-2012 Canonical Ltd.
+
+`,
+			major: 2,
+			minor: 10,
+		},
+		{
+			output: `AppArmor parser version 2.8
+Copyright (C) 1999-2008 Novell Inc.
+Copyright 2009-2012 Canonical Ltd.
+
+`,
+			major: 2,
+			minor: 8,
+		},
+		{
+			output: `AppArmor parser version 2.20
+Copyright (C) 1999-2008 Novell Inc.
+Copyright 2009-2012 Canonical Ltd.
+
+`,
+			major: 2,
+			minor: 20,
+		},
+		{
+			output: `AppArmor parser version 2.05
+Copyright (C) 1999-2008 Novell Inc.
+Copyright 2009-2012 Canonical Ltd.
+
+`,
+			major: 2,
+			minor: 5,
+		},
+	}
+
+	for _, v := range versions {
+		major, minor, err := parseVersion(v.output)
+		if err != nil {
+			t.Fatalf("expected error to be nil for %#v, got: %v", v, err)
+		}
+		if major != v.major {
+			t.Fatalf("expected major version to be %d, was %d, for: %#v\n", v.major, major, v)
+		}
+		if minor != v.minor {
+			t.Fatalf("expected minor version to be %d, was %d, for: %#v\n", v.minor, minor, v)
+		}
+	}
+}