docs: add TA0002 rule page

content/docs/analyzers/TestAutomationCop/TA0002.md

@@ -0,0 +1,107 @@
++++
+title = 'Actions cannot be invoked on a part page opened directly through its own TestPage variable'
+linkTitle = 'TA0002'
+
+[params]
+  id = 'TA0002'
+  severity = 'Warning'
+  category = 'Usage'
+  codeAction = false
+  ignoreObsolete = false
++++
+
+A `ListPart` or `CardPart` page opened directly through its own `TestPage` variable renders no actions at runtime. The platform resolves actions only when the part is hosted inside another page and reached through its `part(...)` control. Calling `Invoke()`, `Enabled()`, or `Visible()` on any action of a directly opened part page fails with:
+
+> The action with ID = xxx is not found on the page.
+
+To reach the action in a test, open the hosting page and invoke the action through the part control: `MainPage.SubPagePart.MyAction.Invoke()`.
+
+### Example
+
+{{< highlight al "hl_lines=25" >}}
+page 50100 "Item Subpage"
+{
+    PageType = ListPart;
+    SourceTable = Item;
+
+    actions
+    {
+        area(processing)
+        {
+            action(UpdatePrices) { }
+        }
+    }
+}
+
+codeunit 50100 "Item Test"
+{
+    Subtype = Test;
+
+    [Test]
+    procedure PriceUpdateTest()
+    var
+        ItemSubPage: TestPage "Item Subpage";
+    begin
+        ItemSubPage.OpenView();
+        ItemSubPage.UpdatePrices.Invoke(); // Action 'UpdatePrices' cannot be invoked on page 'Item Subpage' opened directly because its PageType is ListPart; invoke it through the part control of the hosting page instead. [TA0002]
+    end;
+}
+{{< /highlight >}}
+
+Open the hosting page instead and invoke the action through its part control.
+
+{{< highlight al "hl_lines=25" >}}
+page 50101 "Item Card"
+{
+    PageType = Card;
+    SourceTable = Item;
+
+    layout
+    {
+        area(content)
+        {
+            part(ItemLines; "Item Subpage") { }
+        }
+    }
+}
+
+codeunit 50100 "Item Test"
+{
+    Subtype = Test;
+
+    [Test]
+    procedure PriceUpdateTest()
+    var
+        ItemCard: TestPage "Item Card";
+    begin
+        ItemCard.OpenView();
+        ItemCard.ItemLines.UpdatePrices.Invoke();
+    end;
+}
+{{< /highlight >}}
+
+### When the diagnostic is reported
+
+- The receiver is a `TestPage` variable (local, global, or `var` parameter) whose target page has `PageType = ListPart` or `PageType = CardPart`.
+- The call is `Invoke()`, `Enabled()`, or `Visible()` on any action of that page — these are the only members of the built-in `TestAction` class, and all three fail identically at runtime.
+- Actions added by a `pageextension` that extends the part page are included.
+- Obsolete code is not exempt: an obsolete part page, an `[Obsolete]` test method and an `ObsoleteState = Pending` test codeunit are all reported, because the test runner still executes the test and the runtime failure is real.
+
+### Exception
+
+The diagnostic is not raised for:
+
+- **Field access** on a directly opened part page — fields work without the hosting page.
+- **`OpenView()`, `OpenEdit()`, `OpenNew()`** and other `TestPage` built-in methods — these are not `TestAction` members.
+- **Built-in system actions** `OK()`, `Cancel()`, `Yes()`, `No()`, `View()`, `Edit()` — these are methods of the `TestPage` itself, not actions declared on the part page.
+- **`TestRequestPage`** variables — request pages are not `ListPart` or `CardPart`.
+
+```al
+#pragma warning disable TA0002 // This test deliberately asserts the platform error for an action on a directly opened part.
+    asserterror ItemSubPage.UpdatePrices.Invoke();
+#pragma warning restore TA0002
+```
+
+### See also
+
+- [TestPage Data Type](https://learn.microsoft.com/en-us/dynamics365/business-central/dev-itpro/developer/methods-auto/testpage/testpage-data-type) on Microsoft Learn

content/docs/analyzers/TestAutomationCop/_index.md

@@ -4,10 +4,11 @@ type: docs
 no_list: true
 ---
 
-TestAutomationCop inspects test codeunits and is silent on production code. It flags test procedures whose structure or attributes keep the test runner from executing them as intended, such as a global procedure in a test codeunit that is not marked as a test method.
+TestAutomationCop inspects test codeunits and is silent on production code. It flags test code whose structure keeps the test runner from executing it as intended, such as a missing `[Test]` attribute or an action invoked on a part page that renders no actions at runtime.
 
 ## Rules
 
 | ID | Title | Severity | Enabled | Code Fix |
 |---|---|---|---|---|
 | [TA0001](ta0001/) | Global procedures in test codeunits must be test methods | Warning | ✓ | |
+| [TA0002](ta0002/) | Actions cannot be invoked on a part page opened directly through its own TestPage variable | Warning | ✓ | |