Added test for get_imei()

spec/utisl_spec.lua

@@ -105,6 +105,58 @@ Read result:
 
   end)
 
+  describe("Skyweave IMEI Retrieval", function()
+
+    before_each(function()
+      _G.original_execute_command = utils.execute_command
+    end)
+
+    after_each(function()
+      utils.execute_command = _G.original_execute_command
+      _G.original_execute_command = nil
+    end)
+
+    it("should correctly parse a valid IMEI from uqmi output", function()
+
+      -- 1. Define the simulated output from a successful `uqmi --get-imei` invocation.
+      local mock_uqmi_output = '"015647000004953"'
+
+      -- 2. Mock the command executor to return our simulated data.
+      utils.execute_command = function(command)
+        assert.are.equal("uqmi -d /dev/cdc-wdm0 --get-imei", command)
+        return mock_uqmi_output
+      end
+
+      -- 3. Execute the function under test.
+      local imei, err = utils.get_modem_imei()
+
+      -- 4. Assert the expected outcome.
+      assert.is_nil(err)
+      assert.are.equal("015647000004953", imei)
+    end)
+
+    it("should return an error on nil or empty command output", function()
+      utils.execute_command = function()
+        return nil
+      end
+
+      local imei, err = utils.get_modem_imei()
+      assert.is_nil(imei)
+      assert.are.equal("No output from uqmi --get-imei command", err)
+    end)
+
+    it("should return an error if the IMEI cannot be parsed", function()
+      local malformed_output = "Couldn't get IMEI: QMI protocol error: 'InvalidHandle'"
+      utils.execute_command = function()
+        return malformed_output
+      end
+
+      local imei, err = utils.get_modem_imei()
+      assert.is_nil(imei)
+      assert.are.equal("Failed to parse IMEI from uqmi output", err)
+    end)
+  end)
+
   -- more 'describe' blocks here to test other functions in utils.lua
 
 end)