diff --git a/.ls-lint.yml b/.ls-lint.yml
index 610218f8ed2..22f08f72938 100644
--- a/.ls-lint.yml
+++ b/.ls-lint.yml
@@ -11,14 +11,14 @@ _cfg: &cfg
 
 ls:
    <<: *cfg
-   src:
+   src: &src
       <<: *cfg
       .dir: kebab-case | regex:@types
       .js: exists:0
    src/system/version-migration/versions:
       .ts: snake_case
       <<: *cfg
-
+   test: *src
 ignore:
    - node_modules
    - .vscode
diff --git a/package.json b/package.json
index 9bba5e56f89..02d063389b7 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "@types/jsdom": "^21.1.7",
     "@types/node": "^22.16.3",
     "@vitest/coverage-istanbul": "^3.2.4",
+    "@vitest/expect": "^3.2.4",
     "chalk": "^5.4.1",
     "dependency-cruiser": "^16.10.4",
     "inquirer": "^12.7.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index e77bf065fd5..86a7bb904a1 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -57,6 +57,9 @@ importers:
       '@vitest/coverage-istanbul':
         specifier: ^3.2.4
         version: 3.2.4(vitest@3.2.4(@types/node@22.16.3)(jsdom@26.1.0)(msw@2.10.4(@types/node@22.16.3)(typescript@5.8.3))(yaml@2.8.0))
+      '@vitest/expect':
+        specifier: ^3.2.4
+        version: 3.2.4
       chalk:
         specifier: ^5.4.1
         version: 5.4.1
diff --git a/test/@types/vitest.d.ts b/test/@types/vitest.d.ts
new file mode 100644
index 00000000000..3a0a0fec9cf
--- /dev/null
+++ b/test/@types/vitest.d.ts
@@ -0,0 +1,26 @@
+import type { Pokemon } from "#field/pokemon";
+import type { PokemonType } from "#enums/pokemon-type";
+import type { expect } from "vitest";
+import { toHaveTypesOptions } from "#test/test-utils/matchers/to-have-types";
+
+declare module "vitest" {
+  interface Assertion {
+    /**
+     * Matcher to check if an array contains EXACTLY the given items (in any order).
+     *
+     * Different from {@linkcode expect.arrayContaining} as the latter only requires the array contain
+     * _at least_ the listed items.
+     *
+     * @param expected - The expected contents of the array, in any order.
+     * @see {@linkcode expect.arrayContaining}
+     */
+    toEqualArrayUnsorted<E>(expected: E[]): void;
+    /**
+     * Matcher to check if a {@linkcode Pokemon}'s current typing includes the given types.
+     *
+     * @param expected - The expected types (in any order).
+     * @param options - The options passed to the matcher.
+     */
+    toHaveTypes(expected: PokemonType[], options?: toHaveTypesOptions): void;
+  }
+}
\ No newline at end of file
diff --git a/test/matchers.setup.ts b/test/matchers.setup.ts
new file mode 100644
index 00000000000..7fd5fcb463e
--- /dev/null
+++ b/test/matchers.setup.ts
@@ -0,0 +1,14 @@
+import { toEqualArrayUnsorted } from "#test/test-utils/matchers/to-equal-array-unsorted";
+import { toHaveTypes } from "#test/test-utils/matchers/to-have-types";
+import { expect } from "vitest";
+
+/**
+ * @module
+ * Setup file for custom matchers.
+ * Make sure to define the call signatures in `test/@types/vitest.d.ts` too!
+ */
+
+expect.extend({
+  toEqualArrayUnsorted,
+  toHaveTypes,
+});
diff --git a/test/test-utils/matchers/to-equal-array-unsorted.ts b/test/test-utils/matchers/to-equal-array-unsorted.ts
new file mode 100644
index 00000000000..0627623bbd9
--- /dev/null
+++ b/test/test-utils/matchers/to-equal-array-unsorted.ts
@@ -0,0 +1,43 @@
+import type { MatcherState, SyncExpectationResult } from "@vitest/expect";
+
+/**
+ * Matcher to check if an array contains exactly the given items, disregarding order.
+ * @param received - The object to check. Should be an array of elements.
+ * @returns The result of the matching
+ */
+export function toEqualArrayUnsorted(this: MatcherState, received: unknown, expected: unknown): SyncExpectationResult {
+  if (!Array.isArray(received)) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected an array, but got ${this.utils.stringify(received)}!`,
+    };
+  }
+
+  if (!Array.isArray(expected)) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected to recieve an array, but got ${this.utils.stringify(expected)}!`,
+    };
+  }
+
+  if (received.length !== expected.length) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected to recieve array of length ${received.length}, but got ${expected.length}!`,
+      actual: received,
+      expected,
+    };
+  }
+
+  const gotSorted = received.slice().sort();
+  const wantSorted = expected.slice().sort();
+  const pass = this.equals(gotSorted, wantSorted, [...this.customTesters, this.utils.iterableEquality]);
+
+  return {
+    pass: this.isNot !== pass,
+    message: () =>
+      `Expected ${this.utils.stringify(received)} to exactly equal ${this.utils.stringify(expected)} without order!`,
+    actual: gotSorted,
+    expected: wantSorted,
+  };
+}
diff --git a/test/test-utils/matchers/to-have-types.ts b/test/test-utils/matchers/to-have-types.ts
new file mode 100644
index 00000000000..d09f4fc5f76
--- /dev/null
+++ b/test/test-utils/matchers/to-have-types.ts
@@ -0,0 +1,64 @@
+import { PokemonType } from "#enums/pokemon-type";
+import { Pokemon } from "#field/pokemon";
+import type { MatcherState, SyncExpectationResult } from "@vitest/expect";
+
+export interface toHaveTypesOptions {
+  /**
+   * Whether to enforce exact matches (`true`) or superset matches (`false`).
+   * @defaultValue `true`
+   */
+  exact?: boolean;
+  /**
+   * Optional arguments to pass to {@linkcode Pokemon.getTypes}.
+   */
+  args?: Parameters<(typeof Pokemon.prototype)["getTypes"]>;
+}
+
+/**
+ * Matcher to check if an array contains exactly the given items, disregarding order.
+ * @param received - The object to check. Should be an array of one or more {@linkcode PokemonType}s.
+ * @param options - The {@linkcode toHaveTypesOptions | options} for this matcher
+ * @returns The result of the matching
+ */
+export function toHaveTypes(
+  this: MatcherState,
+  received: unknown,
+  expected: unknown,
+  options: toHaveTypesOptions = {},
+): SyncExpectationResult {
+  if (!(received instanceof Pokemon)) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected a Pokemon, but got ${this.utils.stringify(received)}!`,
+    };
+  }
+
+  if (!Array.isArray(expected) || expected.length === 0) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected to recieve an array with length >=1, but got ${this.utils.stringify(expected)}!`,
+    };
+  }
+
+  if (!expected.every((t): t is PokemonType => t in PokemonType)) {
+    return {
+      pass: this.isNot,
+      message: () => `Expected to recieve array of PokemonTypes but got ${this.utils.stringify(expected)}!`,
+    };
+  }
+
+  const gotSorted = pkmnTypeToStr(received.getTypes(...(options.args ?? [])));
+  const wantSorted = pkmnTypeToStr(expected.slice());
+  const pass = this.equals(gotSorted, wantSorted, [...this.customTesters, this.utils.iterableEquality]);
+
+  return {
+    pass: this.isNot !== pass,
+    message: () => `Expected ${received.name} to have types ${this.utils.stringify(wantSorted)}, but got ${gotSorted}!`,
+    actual: gotSorted,
+    expected: wantSorted,
+  };
+}
+
+function pkmnTypeToStr(p: PokemonType[]): string[] {
+  return p.sort().map(type => PokemonType[type]);
+}
diff --git a/vitest.config.ts b/vitest.config.ts
index e788302857b..65c5427e591 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -9,7 +9,7 @@ export default defineProject(({ mode }) => ({
       TZ: "UTC",
     },
     testTimeout: 20000,
-    setupFiles: ["./test/font-face.setup.ts", "./test/vitest.setup.ts"],
+    setupFiles: ["./test/font-face.setup.ts", "./test/vitest.setup.ts", "./test/matchers.setup.ts"],
     sequence: {
       sequencer: MySequencer,
     },