Add error message match to shallRevert assertion (#129)

onflow · Jul 5, 2022 · 78944c1 · 78944c1
1 parent ba2de53
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diff --git a/.changeset/wet-pillows-applaud.md b/.changeset/wet-pillows-applaud.md
@@ -0,0 +1,5 @@
+---
+"@onflow/flow-js-testing": minor
+---
+
+Add optional error message match to shallRevert Jest assertion
diff --git a/docs/api.md b/docs/api.md
@@ -654,15 +654,17 @@ describe("interactions - sendTransaction", () => {
 });
 ```
 
-### shallRevert(ix)
+## shallRevert(ix, message)
 
-Ensure interaction throws an error. You might want to use this to test incorrect inputs.
+Ensure interaction throws an error. Can test for specific error messages or catch any error message if `message` is not provided.
+Returns Promise, which contains result, when resolved.
 
 #### Arguments
 
-| Name | Type                        | Description                                          |
-| ---- | --------------------------- | ---------------------------------------------------- |
-| `ix` | [Interaction](#interaction) | transaction, either in form of a Promise or function |
+| Name                     | Type                              | Description                                                                                                              |
+| ------------------------ | --------------------------------- | ------------------------------------------------------------------------------------------------------------------------ |
+| `ix`                     | [Interaction](api.md#interaction) | transaction, either in form of a Promise or function                                                                     |
+| `message` **(optional)** | `string` or `RegExp`              | expected error message provided as either a string equality or regular expression to match, matches any error by default |
 
 #### Returns
 

diff --git a/docs/jest-helpers.md b/docs/jest-helpers.md
@@ -71,16 +71,17 @@ describe("interactions - sendTransaction", () => {
 });
 ```
 
-## shallRevert(ix)
+## shallRevert(ix, message)
 
-Ensure interaction throws an error. Use this to test incorrect inputs.
+Ensure interaction throws an error. Can test for specific error messages or catch any error message if `message` is not provided.
 Returns Promise, which contains result, when resolved.
 
 #### Arguments
 
-| Name | Type                              | Description                                          |
-| ---- | --------------------------------- | ---------------------------------------------------- |
-| `ix` | [Interaction](api.md#interaction) | transaction, either in form of a Promise or function |
+| Name                     | Type                              | Description                                                                                                              |
+| ------------------------ | --------------------------------- | ------------------------------------------------------------------------------------------------------------------------ |
+| `ix`                     | [Interaction](api.md#interaction) | transaction, either in form of a Promise or function                                                                     |
+| `message` **(optional)** | `string` or `RegExp`              | expected error message provided as either a string equality or regular expression to match, matches any error by default |
 
 #### Returns
 

diff --git a/src/jest-asserts.js b/src/jest-asserts.js
@@ -80,14 +80,29 @@ export const shallResolve = async (ix) => {
 /**
  * Ensure interaction throws an error.
  * @param {function | Promise} ix - Promise or function to wrap
+ * @param {string | RegExp} [message] - Expected error message provided as either a string equality or regular expression
  * @returns Promise<*> -  result of interaction
  * */
-export const shallRevert = async (ix) => {
+export const shallRevert = async (ix, message) => {
   const wrappedInteraction = promise(ix);
   const response = await wrappedInteraction;
   const [result, error] = response;
+
   await expect(result).toBe(null);
-  await expect(error).not.toBe(null);
+
+  if (message) {
+    const errorMessage = error
+      .toString()
+      .match(/^error: (panic)|(assertion failed): ([^\r\n]*)$/m)
+      ?.at(3);
+    if (message instanceof RegExp) {
+      await expect(errorMessage).toMatch(message);
+    } else {
+      await expect(errorMessage).toBe(message);
+    }
+  } else {
+    await expect(error).not.toBe(null);
+  }
 
   return response;
 };