diff --git a/Package.swift b/Package.swift
index d83cee07..3354110d 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.1
+// swift-tools-version:5.3
 
 import PackageDescription
 
diff --git a/Tests/SteviaTests/BaselineTests.swift b/Tests/SteviaTests/BaselineTests.swift
index 282a29ee..1213b921 100644
--- a/Tests/SteviaTests/BaselineTests.swift
+++ b/Tests/SteviaTests/BaselineTests.swift
@@ -16,8 +16,6 @@ class BaselineTests: XCTestCase {
     var label1 = UILabel()
     var label2 = UILabel()
     
-
-    
     override func setUp() {
         win = UIWindow(frame: UIScreen.main.bounds)
         ctrler =  UIViewController()
diff --git a/Tests/SteviaTests/CenterTests.swift b/Tests/SteviaTests/CenterTests.swift
index e0205795..cadf6ce4 100644
--- a/Tests/SteviaTests/CenterTests.swift
+++ b/Tests/SteviaTests/CenterTests.swift
@@ -22,7 +22,7 @@ class CenterTests: XCTestCase {
         ctrler =  UIViewController()
         win.rootViewController = ctrler
         v = UIView()
-        ctrler.view.subviews { v }
+        ctrler.view.subviews { v! }
         
         // verify view h as default values
         XCTAssertEqual(v.frame.origin.y, 0, accuracy: CGFloat(Float.ulpOfOne))
diff --git a/Tests/SteviaTests/FlexibleMarginTests.swift b/Tests/SteviaTests/FlexibleMarginTests.swift
index b9251f88..f3f26842 100644
--- a/Tests/SteviaTests/FlexibleMarginTests.swift
+++ b/Tests/SteviaTests/FlexibleMarginTests.swift
@@ -21,7 +21,7 @@ class FlexibleMarginTests: XCTestCase {
         ctrler =  UIViewController()
         win.rootViewController = ctrler
         v = UIView()
-        ctrler.view.subviews { v }
+        ctrler.view.subviews { v! }
         v.size(100.0)
     }
     
diff --git a/Tests/SteviaTests/FullLayoutTests.swift b/Tests/SteviaTests/FullLayoutTests.swift
index 356b698b..26960413 100644
--- a/Tests/SteviaTests/FullLayoutTests.swift
+++ b/Tests/SteviaTests/FullLayoutTests.swift
@@ -84,7 +84,7 @@ class FullLayoutTests: XCTestCase {
         v.layoutIfNeeded()
 
         // Email
-        XCTAssertEqual(v.email.frame.origin.y, 100.5, accuracy: CGFloat(Float.ulpOfOne))
+        XCTAssertEqual(v.email.frame.origin.y, 100.5, accuracy: 0.5)
         XCTAssertEqual(v.email.frame.origin.x, 8, accuracy: CGFloat(Float.ulpOfOne))
         XCTAssertEqual(v.email.frame.width, win.frame.width - 8 - 22,
                                    accuracy: CGFloat(Float.ulpOfOne))
@@ -120,7 +120,7 @@ class FullLayoutTests: XCTestCase {
         v.layoutIfNeeded()
 
         // Email
-        XCTAssertEqual(v.email.frame.origin.y, 100.5, accuracy: CGFloat(Float.ulpOfOne))
+        XCTAssertEqual(v.email.frame.origin.y, 100.5, accuracy: 0.5)
         XCTAssertEqual(v.email.frame.origin.x, 22, accuracy: CGFloat(Float.ulpOfOne))
         XCTAssertEqual(v.email.frame.width, win.frame.width - 8 - 22,
                                    accuracy: CGFloat(Float.ulpOfOne))
diff --git a/Tests/SteviaTests/GetConstraintsTests.swift b/Tests/SteviaTests/GetConstraintsTests.swift
index d6e369c0..2a33b2fa 100644
--- a/Tests/SteviaTests/GetConstraintsTests.swift
+++ b/Tests/SteviaTests/GetConstraintsTests.swift
@@ -17,7 +17,7 @@ class GetConstraintsTests: XCTestCase {
     override func setUp() {
         spv = UIView()
         v = UIView()
-        spv.subviews { v }
+        spv.subviews { v! }
     }
     
     func testCanGetLeftConstraint() {
diff --git a/Tests/SteviaTests/LayoutTests.swift b/Tests/SteviaTests/LayoutTests.swift
index 24783671..77a0628f 100644
--- a/Tests/SteviaTests/LayoutTests.swift
+++ b/Tests/SteviaTests/LayoutTests.swift
@@ -21,7 +21,7 @@ class LayoutTests: XCTestCase {
         ctrler =  UIViewController()
         win.rootViewController = ctrler
         v = UIView()
-        ctrler.view.subviews { v }
+        ctrler.view.subviews { v! }
         verifyViewHasDefaultValues()
     }
     
diff --git a/Tests/SteviaTests/PositionTests.swift b/Tests/SteviaTests/PositionTests.swift
index 4b3926cd..e20af419 100644
--- a/Tests/SteviaTests/PositionTests.swift
+++ b/Tests/SteviaTests/PositionTests.swift
@@ -21,7 +21,7 @@ class PositionTests: XCTestCase {
         ctrler =  UIViewController()
         win.rootViewController = ctrler
         v = UIView()
-        ctrler.view.subviews {v }
+        ctrler.view.subviews { v! }
         v.size(100.0)
     }
     
diff --git a/Tests/SteviaTests/SizeTests.swift b/Tests/SteviaTests/SizeTests.swift
index c8cf226c..b1b6fef1 100644
--- a/Tests/SteviaTests/SizeTests.swift
+++ b/Tests/SteviaTests/SizeTests.swift
@@ -22,7 +22,7 @@ class SizeTests: XCTestCase {
         win.rootViewController = ctrler
         v = UIView()
         ctrler.view.subviews {
-            v
+            v!
         }
     }
     
@@ -207,7 +207,7 @@ class SizeTests: XCTestCase {
         v.removeFromSuperview()
         v.height(80)
         v.width(80)
-        ctrler.view?.subviews { v }
+        ctrler.view?.subviews { v! }
         
         let view: UIView = ctrler.view
         view.layout {
diff --git a/Tests/SteviaTests/StyleTests.swift b/Tests/SteviaTests/StyleTests.swift
index 55a9e3da..326b2ecc 100644
--- a/Tests/SteviaTests/StyleTests.swift
+++ b/Tests/SteviaTests/StyleTests.swift
@@ -37,6 +37,4 @@ class StyleTests: XCTestCase {
         }
         XCTAssertEqual(label.textColor, UIColor.blue)
     }
-
-
 }