feat(dom): DOM - toHaveSomeStyle (#158)

Author: SbsCruz

packages/dom/src/lib/ElementAssertion.ts

@@ -216,6 +216,50 @@ export class ElementAssertion<T extends Element> extends Assertion<T> {
     });
     }
 
+  /**
+   * Asserts that the element has one or more of the specified CSS styles.
+   *
+   * @example
+   * ```
+   * expect(component).toHaveSomeStyle({ color: 'green', display: 'block' });
+   * ```
+   *
+   * @param expected the expected CSS style/s.
+   * @returns the assertion instance.
+   */
+
+  public toHaveSomeStyle(expected: Partial<CSSStyleDeclaration>): this {
+
+    const [expectedStyle, elementProcessedStyle] = getExpectedAndReceivedStyles(this.actual, expected);
+
+    if (!expectedStyle || !elementProcessedStyle) {
+      throw new Error("No available styles.");
+    }
+
+    const hasSomeStyle = Object.entries(expectedStyle).some(([expectedProp, expectedValue]) => {
+      return Object.entries(elementProcessedStyle).some(([receivedProp, receivedValue]) => {
+        return equal(expectedProp, receivedProp) && equal(expectedValue, receivedValue);
+      });
+    });
+
+    const error = new AssertionError({
+      actual: this.actual,
+      message: `Expected the element to match some of the following styles:\n${JSON.stringify(expectedStyle, null, 2)}`,
+    });
+
+    const invertedError = new AssertionError({
+      actual: this.actual,
+      // eslint-disable-next-line max-len
+      message: `Expected the element NOT to match some of the following styles:\n${JSON.stringify(expectedStyle, null, 2)}`,
+    });
+
+    return this.execute({
+      assertWhen: hasSomeStyle,
+      error,
+      invertedError,
+    });
+  }
+
   /**
    * Helper method to assert the presence or absence of class names.
    *

packages/dom/test/unit/lib/ElementAssertion.test.tsx

@@ -368,4 +368,47 @@ describe("[Unit] ElementAssertion.test.ts", () => {
         });
     });
   });
+
+  describe(".toHaveSomeStyle", () => {
+    context("when the element contains one or more expected styles", () => {
+      it("returns the assertion instance", () => {
+        const { getByTestId } = render(
+            <div
+              style={{ color: "blue", maxHeight: "3rem", width: "2rem" }}
+              data-testid="test-div"
+            />,
+          );
+        const divTest = getByTestId("test-div");
+        const test = new ElementAssertion(divTest);
+
+        expect(test.toHaveSomeStyle({ color: "red", display: "flex", height: "3rem", width: "2rem" })).toBeEqual(test);
+
+        expect(() => test.not.toHaveSomeStyle({ color: "blue" }))
+        .toThrowError(AssertionError)
+        // eslint-disable-next-line max-len
+        .toHaveMessage("Expected the element NOT to match some of the following styles:\n{\n  \"color\": \"rgb(0, 0, 255)\"\n}");
+      });
+    });
+
+    context("when the element does not contain any of the expected styles", () => {
+      it("throws an assertion error", () => {
+        const { getByTestId } = render(
+            <div
+              className="foo bar test"
+              style={{ border: "1px solid black", color: "blue", display: "block" }}
+              data-testid="test-div"
+            />,
+          );
+        const divTest = getByTestId("test-div");
+        const test = new ElementAssertion(divTest);
+
+        expect(() => test.toHaveSomeStyle({ color: "red", display: "flex" }))
+        .toThrowError(AssertionError)
+        // eslint-disable-next-line max-len
+        .toHaveMessage("Expected the element to match some of the following styles:\n{\n  \"color\": \"rgb(255, 0, 0)\",\n  \"display\": \"flex\"\n}");
+
+        expect(test.not.toHaveSomeStyle({ border: "1px solid blue", color: "red", display: "flex" })).toBeEqual(test);
+      });
+    });
+  });
 });