"lib list" now returns an empty json array when there are no librarie…

…s installed (#511)

* add test for #443

* return an empty json array when there are no libs

cli/lib/list.go

@@ -65,8 +65,14 @@ func runListCommand(cmd *cobra.Command, args []string) {
 	}
 
 	libs := res.GetInstalledLibrary()
-	feedback.PrintResult(installedResult{libs})
 
+	// To uniform the output to other commands, when there are no result
+	// print out an empty slice.
+	if libs == nil {
+		libs = []*rpc.InstalledLibrary{}
+	}
+
+	feedback.PrintResult(installedResult{libs})
 	logrus.Info("Done")
 }
 

test/test_lib.py

@@ -27,7 +27,7 @@ def test_list(run_command):
     result = run_command("lib list --format json")
     assert result.ok
     assert "" == result.stderr
-    assert "null" == result.stdout
+    assert 0 == len(json.loads(result.stdout))
 
     # Install something we can list at a version older than latest
     result = run_command("lib install ArduinoJson@6.11.0")
@@ -70,13 +70,21 @@ def test_update_index(run_command):
     )
 
 
-def test_remove(run_command):
-    libs = ['"AzureIoTProtocol_MQTT"', '"CMMC MQTT Connector"', '"WiFiNINA"']
+def test_uninstall(run_command):
+    libs = ['"AzureIoTProtocol_MQTT"', '"WiFiNINA"']
     assert run_command("lib install {}".format(" ".join(libs)))
 
     result = run_command("lib uninstall {}".format(" ".join(libs)))
     assert result.ok
 
+def test_uninstall_spaces(run_command):
+    key = '"LiquidCrystal I2C"'
+    assert run_command("lib install {}".format(key))
+    assert run_command("lib uninstall {}".format(key))
+    result = run_command("lib list --format json")
+    assert result.ok
+    assert len(json.loads(result.stdout)) == 0
+
 
 def test_search(run_command):
     assert run_command("lib update-index")