test: add formatMessage tests

src/__tests__/__snapshots__/formatMessage.test.js.snap

@@ -0,0 +1,13 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`formatMessage returns a list of strings suitable for console logging 1`] = `
+Array [
+  "%c apollo %cquery %cFormatMessageQuery %c(in 1000 ms)",
+]
+`;
+
+exports[`formatMessage returns a list of strings suitable for console logging 2`] = `
+Array [
+  "%c apollo %cmutation %cFormatMessageMutation %c(in 500 ms)",
+]
+`;

src/__tests__/formatMessage.test.js

@@ -0,0 +1,17 @@
+const formatMessage = require('../formatMessage');
+
+describe('formatMessage', () => {
+  it('returns a list of strings suitable for console logging', () => {
+    expect(
+      formatMessage('query', { operationName: 'FormatMessageQuery' }, 1000),
+    ).toMatchSnapshot();
+
+    expect(
+      formatMessage(
+        'mutation',
+        { operationName: 'FormatMessageMutation' },
+        500,
+      ),
+    ).toMatchSnapshot();
+  });
+});