feat(sounds): mute and unmute subcommands

test/nag.bats

@@ -304,3 +304,26 @@ SCRIPT
   [[ "${output}" =~ "Usage:" ]]
   [[ "${output}" =~ "check" ]]
 }
+
+# mute/unmute #################################################################
+
+@test "mute creates muted file" {
+  run_nag mute
+  [ "${status}" -eq 0 ]
+  [[ "${output}" =~ "muted" ]]
+  [ -f "${NAG_DIR}/muted" ]
+}
+
+@test "unmute removes muted file" {
+  run_nag mute
+  run_nag unmute
+  [ "${status}" -eq 0 ]
+  [[ "${output}" =~ "unmuted" ]]
+  [ ! -f "${NAG_DIR}/muted" ]
+}
+
+@test "unmute when not muted says so" {
+  run_nag unmute
+  [ "${status}" -eq 0 ]
+  [[ "${output}" =~ "not muted" ]]
+}