Add toBePartiallyChecked matcher

src/JestDom.re

@@ -139,6 +139,11 @@ let toHaveDisplayValue = value => value->_toHaveDisplayValue->pass;
 
 let toBeChecked = _toBeChecked->pass;
 
+[@bs.send.pipe: expect]
+external _toBePartiallyChecked: unit = "toBePartiallyChecked";
+
+let toBePartiallyChecked = _toBePartiallyChecked->pass;
+
 [@bs.send.pipe: expect]
 external _toHaveDescription:
   ([@bs.unwrap] [ | `Str(string) | `RegExp(Js.Re.t)]) => unit =

src/JestDom.rei

@@ -52,5 +52,6 @@ let toHaveValue:
 let toHaveDisplayValue:
   ([ | `Str(string) | `RegExp(Js.Re.t) | `Arr(array(string))], expect) => Jest.assertion;
 let toBeChecked: expect => Jest.assertion;
+let toBePartiallyChecked: expect => Jest.assertion;
 let toHaveDescription:
   ([ | `Str(string) | `RegExp(Js.Re.t)], expect) => Jest.assertion;

src/__tests__/JestDom_test.re

@@ -494,6 +494,21 @@ test("not toBeChecked", () =>
   |> toBeChecked
 );
 
+test("toBePartiallyChecked", () =>
+  render({|<input type="checkbox" aria-checked="mixed" data-testid="input" />|})
+  |> queryByTestId("input")
+  |> expect
+  |> toBePartiallyChecked
+);
+
+test("not toBePartiallyChecked", () =>
+  render({|<input type="checkbox" checked data-testid="input" />|})
+  |> queryByTestId("input")
+  |> expect
+  |> not_
+  |> toBePartiallyChecked
+);
+
 test("toHaveDescription (string)", () =>
   render({|<span><button data-testid="button" aria-label="Close" aria-describedby="description-close">X</button><div id="description-close">Closing will discard any changes</div></span>|})
   |> queryByTestId("button")