Share the run function for better tests

lydell · Oct 27, 2023 · 05f1c4f · 05f1c4f
1 parent d48c8ea
commit 05f1c4f
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Showing 5 changed files with 49 additions and 88 deletions.
diff --git a/examples/extra-fields.test.ts b/examples/extra-fields.test.ts
@@ -1,6 +1,7 @@
 import { expect, test } from "vitest";
 
-import { Decoder, fieldsAuto, format, map, number, string } from "..";
+import { Decoder, fieldsAuto, map, number, string } from "..";
+import { run } from "../tests/helpers";
 
 test("adding extra fields to records", () => {
   // Want to add an extra field to a record, that doesn’t look at the input at
@@ -43,17 +44,12 @@ test("adding extra fields to records", () => {
   });
 
   // It no longer works, because all the fields you mentioned are expected to exist.
-  const decoderResult = productDecoderBroken(data);
-  expect(
-    decoderResult.tag === "DecoderError"
-      ? format(decoderResult.error)
-      : decoderResult,
-  ).toMatchInlineSnapshot(`
-    "At root:
-    Expected an object with a field called: \\"version\\"
+  expect(run(productDecoderBroken, data)).toMatchInlineSnapshot(`
+    At root:
+    Expected an object with a field called: "version"
     Got: {
-      \\"name\\": \\"Comfortable Bed\\",
-      \\"price\\": 10000
-    }"
+      "name": "Comfortable Bed",
+      "price": 10000
+    }
   `);
 });
diff --git a/examples/fieldsUnion-fallback.test.ts b/examples/fieldsUnion-fallback.test.ts
@@ -2,6 +2,7 @@ import { expectType, TypeEqual } from "ts-expect";
 import { expect, test } from "vitest";
 
 import { Decoder, fieldsUnion, Infer, number, tag } from "../";
+import { run } from "../tests/helpers";
 
 test("fieldsUnion with fallback for unknown tags", () => {
   // Here’s a helper function that takes a decoder – which is supposed to be a
@@ -65,44 +66,26 @@ test("fieldsUnion with fallback for unknown tags", () => {
   });
 
   // The original decoder fails on unknown tags, while the other one returns `undefined`.
-  expect(decoder({ tag: "Three" })).toMatchInlineSnapshot(`
-    {
-      "error": {
-        "got": "Three",
-        "knownTags": [
-          "One",
-          "Two",
-        ],
-        "path": [
-          "tag",
-        ],
-        "tag": "unknown fieldsUnion tag",
-      },
-      "tag": "DecoderError",
-    }
+  expect(run(decoder, { tag: "Three" })).toMatchInlineSnapshot(`
+    At root["tag"]:
+    Expected one of these tags:
+      "One",
+      "Two"
+    Got: "Three"
   `);
   expect(decoderWithFallback({ tag: "Three" })).toStrictEqual({
     tag: "Valid",
     value: undefined,
   });
 
   // A nested `fieldsUnion` still fails on unknown tags:
-  expect(decoderWithFallback({ tag: "Two", value: { tag: "Rectangle" } }))
-    .toMatchInlineSnapshot(`
-    {
-      "error": {
-        "got": "Rectangle",
-        "knownTags": [
-          "Circle",
-          "Square",
-        ],
-        "path": [
-          "value",
-          "tag",
-        ],
-        "tag": "unknown fieldsUnion tag",
-      },
-      "tag": "DecoderError",
-    }
+  expect(
+    run(decoderWithFallback, { tag: "Two", value: { tag: "Rectangle" } }),
+  ).toMatchInlineSnapshot(`
+    At root["value"]["tag"]:
+    Expected one of these tags:
+      "Circle",
+      "Square"
+    Got: "Rectangle"
   `);
 });
diff --git a/examples/readme.test.ts b/examples/readme.test.ts
@@ -8,33 +8,13 @@ import {
   DecoderResult,
   field,
   fieldsAuto,
-  format,
   Infer,
   number,
   repr,
-  ReprOptions,
   string,
   undefinedOr,
 } from "..";
-
-function run<T>(
-  decoder: Decoder<T>,
-  value: unknown,
-  options?: ReprOptions,
-): T | string {
-  const decoderResult = decoder(value);
-  switch (decoderResult.tag) {
-    case "DecoderError":
-      return format(decoderResult.error, options);
-    case "Valid":
-      return decoderResult.value;
-  }
-}
-
-expect.addSnapshotSerializer({
-  test: (value: unknown): boolean => typeof value === "string",
-  print: String,
-});
+import { run } from "../tests/helpers";
 
 test("the main readme example", () => {
   type User = {
@@ -117,7 +97,7 @@ test("default vs sensitive error messages", () => {
       error instanceof Error ? error.message : `Unknown error: ${repr(error)}`;
   }
 
-  expect(message).toMatchInlineSnapshot("Expected userDecoder to fail!");
+  expect(message).toMatchInlineSnapshot('"Expected userDecoder to fail!"');
 
   expect(run(userDecoder, data)).toMatchInlineSnapshot(`
     At root["details"]["ssn"]:

diff --git a/tests/decoders.test.ts b/tests/decoders.test.ts
@@ -10,41 +10,20 @@ import {
   fieldsAuto,
   fieldsUnion,
   flatMap,
-  format,
   Infer,
   map,
   multi,
   nullable,
   number,
   record,
   recursive,
-  ReprOptions,
   string,
   stringUnion,
   tag,
   tuple,
   undefinedOr,
 } from "..";
-
-function run<T>(
-  decoder: Decoder<T>,
-  value: unknown,
-  options?: ReprOptions,
-): T | string {
-  const decoderResult = decoder(value);
-  switch (decoderResult.tag) {
-    case "DecoderError":
-      return format(decoderResult.error, options);
-    case "Valid":
-      return decoderResult.value;
-  }
-}
-
-expect.addSnapshotSerializer({
-  test: (value: unknown): boolean =>
-    typeof value === "string" && value.includes("At root"),
-  print: String,
-});
+import { run } from "./helpers";
 
 test("boolean", () => {
   expect(boolean(true)).toStrictEqual({ tag: "Valid", value: true });

diff --git a/tests/helpers.ts b/tests/helpers.ts
@@ -0,0 +1,23 @@
+import { expect } from "vitest";
+
+import { Decoder, format, ReprOptions } from "..";
+
+export function run<T>(
+  decoder: Decoder<T>,
+  value: unknown,
+  options?: ReprOptions,
+): T | string {
+  const decoderResult = decoder(value);
+  switch (decoderResult.tag) {
+    case "DecoderError":
+      return format(decoderResult.error, options);
+    case "Valid":
+      return decoderResult.value;
+  }
+}
+
+expect.addSnapshotSerializer({
+  test: (value: unknown): boolean =>
+    typeof value === "string" && value.includes("At root"),
+  print: String,
+});