diff --git a/test-support/index.d.ts b/test-support/index.d.ts
new file mode 100644
index 0000000..e91c6d1
--- /dev/null
+++ b/test-support/index.d.ts
@@ -0,0 +1,30 @@
+export default class TestLoader {
+  /** Instantiates a new TestLoader and loads the modules. */
+  static load(): void;
+
+  /**
+   * Can be overridden in order to customize the criteria for identifying test
+   * modules.
+   */
+  shouldLoadModule(moduleName: string): boolean;
+
+  moduleLoadFailure(moduleName: string, error: unknown): void;
+
+  /** Use `TestLoader.load()` static method instead. */
+  protected constructor();
+
+  // Assumed private:
+  // loadModules(): void;
+  // listModules(): string[];
+  // listTestModules(): string[];
+  // require(moduleName: string): void;
+  // unsee(moduleName: string): void;
+}
+
+export function addModuleExcludeMatcher(
+  matcher: (moduleName: string) => boolean
+): void;
+
+export function addModuleIncludeMatcher(
+  matcher: (moduleName: string) => boolean
+): void;