1 files changed, 65 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/matchers/to_validate_json_schema_spec.js b/spec/frontend/__helpers__/matchers/to_validate_json_schema_spec.js
new file mode 100644
index 00000000000..fd42c710c65
--- /dev/null
+++ b/spec/frontend/__helpers__/matchers/to_validate_json_schema_spec.js
@@ -0,0 +1,65 @@
+import Ajv from 'ajv';
+import AjvFormats from 'ajv-formats';
+
+const JSON_SCHEMA = {
+  type: 'object',
+  properties: {
+    fruit: {
+      type: 'string',
+      minLength: 3,
+    },
+  },
+};
+
+const ajv = new Ajv({
+  strictTypes: false,
+  strictTuples: false,
+  allowMatchingProperties: true,
+});
+
+AjvFormats(ajv);
+const schema = ajv.compile(JSON_SCHEMA);
+
+describe('custom matcher toValidateJsonSchema', () => {
+  it('throws error if validator is not compiled correctly', () => {
+    expect(() => {
+      expect({}).toValidateJsonSchema({});
+    }).toThrow(
+      'Validator must be a validating function with property "schema", created with `ajv.compile`. See https://ajv.js.org/api.html#ajv-compile-schema-object-data-any-boolean-promise-any.',
+    );
+  });
+
+  describe('positive assertions', () => {
+    it.each`
+      description      | input
+      ${'valid input'} | ${{ fruit: 'apple' }}
+    `('schema validation passes for $description', ({ input }) => {
+      expect(input).toValidateJsonSchema(schema);
+    });
+
+    it('throws if not matching', () => {
+      expect(() => expect(null).toValidateJsonSchema(schema)).toThrowError(
+        `Expected the given data to pass the schema validation, but found that it was considered invalid. Errors:
+Error with item : must be object`,
+      );
+    });
+  });
+
+  describe('negative assertions', () => {
+    it.each`
+      description                    | input
+      ${'no input'}                  | ${null}
+      ${'input with invalid type'}   | ${'banana'}
+      ${'input with invalid length'} | ${{ fruit: 'aa' }}
+      ${'input with invalid type'}   | ${{ fruit: 12345 }}
+    `('schema validation fails for $description', ({ input }) => {
+      expect(input).not.toValidateJsonSchema(schema);
+    });
+
+    it('throws if matching', () => {
+      expect(() => expect({ fruit: 'apple' }).not.toValidateJsonSchema(schema)).toThrowError(
+        'Expected the given data not to pass the schema validation, but found that it was considered valid.',
+      );
+    });
+  });
+});