add go plugin tests and update list reversal logic

test/plugins/go.plugin.bats

@@ -0,0 +1,37 @@
+#!/usr/bin/env bats
+
+#load ../test_helper
+load ../../lib/helpers
+load ../../lib/composure
+load ../../plugins/available/go.plugin
+
+@test 'plugins go: reverse path: single entry' {
+  run _split_path_reverse '/foo'
+  echo "output = ${output}"
+  [ "$output" = "/foo" ]
+}
+
+@test 'plugins go: reverse path: single entry, colon empty' {
+  run _split_path_reverse '/foo:'
+  echo "output = ${output}"
+  [ "$output" = "/foo" ]
+}
+
+@test 'plugins go: reverse path: single entry, colon whitespace' {
+  run _split_path_reverse '/foo: '
+  echo "output = ${output}"
+  [ "$output" = "/foo" ]
+}
+
+@test 'plugins go: reverse path: multiple entries' {
+  run _split_path_reverse '/foo:/bar'
+  echo "output = ${output}"
+  [ "$output" = "/bar /foo" ]
+}
+
+@test 'plugins go: multiple entries in GOPATH' {
+  export GOPATH="/foo:/bar"
+  load ../../plugins/available/go.plugin
+  echo "$(echo $PATH | cut -d':' -f1,2)"
+  [ "$(echo $PATH | cut -d':' -f1,2)" = "/foo/bin:/bar/bin" ]
+}