Add test for toml, fix bug returning wrong type

__tests__/args.test.ts

@@ -71,4 +71,17 @@ describe("actions-rs/toolchain", () => {
 
         expect(args.name).toBe("1.39.0");
     });
+
+    it("supports toml override file", function () {
+        const rustToolchainFile = tempWriteSync(`
+            [toolchain]
+            channel = "stable"
+        `);
+
+        const args = morph(() => {
+            return getToolchainArgs(rustToolchainFile);
+        }, {});
+
+        expect(args.name).toBe("stable");
+    });
 });

src/args.ts

@@ -46,9 +46,9 @@ function determineToolchain(overrideFile: string): string {
         throw new Error(`channel is not specified in ${toolchainPath}`);
     }
 
-    debug(`using toolchain from rust-toolchain file: ${rustToolchainFile}`);
+    debug(`using toolchain from rust-toolchain file: ${toolchain}`);
 
-    return rustToolchainFile;
+    return toolchain;
 }
 
 export function getToolchainArgs(overrideFile: string): ToolchainOptions {