     let index4 = array.lastIndex(of: 11)
     XCTAssertTrue(index4 == nil)
   }
-
+  
   func testRandom() {
     do {
       let collection = [1]
       for _ in 1...100 {
-      XCTAssertTrue(collection.random() == 1)
+        XCTAssertTrue(collection.random() == 1)
       }
     }
-
+    
     do {
       let collection = [1, 2]
       for _ in 1...100 {

        XCTAssertTrue(value == 1 || value == 2)
      }
    }

    do {
      let collection = Array(repeating: 3, count: 300)
      XCTAssertTrue(collection.random() == 3)
    }

    do {
      let collection = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20]
      for _ in 1...100 {

@testable import Mechanica

class CollectionUtilsTests: XCTestCase {
  
  func testFirstIndex() {
    // Given
    let array = [1, 1, 1, 2, 3, 4, 4, 5, 8]
    
    // When, Then
    let index1 = array.firstIndex(of: 1)
    XCTAssertTrue(index1 == 0)
