Size Range comparison with epsilon

Summary:
In some cases size range comparison can assert because of rounding issues with floating point numbers.
By adding a comparison with an epsilon we can reduce the cases for false positives.

Reviewed By: Andrey-Mishanin

Differential Revision: D8874248

fbshipit-source-id: 1e6949b5e26c734241401e001bd1a7d7e5523954

Author: Antonio Corrado

ComponentKit/Core/CKComponent.mm

@@ -296,10 +296,10 @@ - (CKComponentLayout)layoutThatFits:(CKSizeRange)constrainedSize parentSize:(CGS
   CKAssert(layout.component == self, @"Layout computed by %@ should return self as component, but returned %@",
            [self class], [layout.component class]);
   CKSizeRange resolvedRange __attribute__((unused)) = constrainedSize.intersect(_size.resolve(parentSize));
-  CKAssertWithCategory(layout.size.width <= resolvedRange.max.width
-                       && layout.size.width >= resolvedRange.min.width
-                       && layout.size.height <= resolvedRange.max.height
-                       && layout.size.height >= resolvedRange.min.height,
+  CKAssertWithCategory(CKIsGreaterThanOrEqualWithTolerance(resolvedRange.max.width, layout.size.width)
+                       && CKIsGreaterThanOrEqualWithTolerance(layout.size.width, resolvedRange.min.width)
+                       && CKIsGreaterThanOrEqualWithTolerance(resolvedRange.max.height,layout.size.height)
+                       && CKIsGreaterThanOrEqualWithTolerance(layout.size.height,resolvedRange.min.height),
                        NSStringFromClass([self class]),
                        @"Computed size %@ for %@ does not fall within constrained size %@\n%@",
                        NSStringFromCGSize(layout.size), [self class], resolvedRange.description(),

ComponentKit/Utilities/CKInternalHelpers.h

@@ -31,6 +31,10 @@ static inline BOOL CKFloatsEqual(const CGFloat a, const CGFloat b) noexcept {
     return fabs(a - b) < 0.0001f;
 }
 
+static inline bool CKIsGreaterThanOrEqualWithTolerance(CGFloat a,CGFloat b) {
+    return a > b || CKFloatsEqual(a, b);
+}
+
 static inline CGFloat CKRoundValueToPixelGrid(CGFloat value, const BOOL forceCeil,
                                               const BOOL forceFloor) noexcept
 {

ComponentKitTests/CKSizeRangeTests.mm

@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2014-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+
+#import <XCTest/XCTest.h>
+#import <ComponentKit/CKInternalHelpers.h>
+#import <ComponentKit/CKSizeRange.h>
+
+@interface CKSizeRangeTests : XCTestCase
+
+@end
+
+@implementation CKSizeRangeTests
+
+static bool verifySizeRange(CKSizeRange &sz,CGSize &size) {
+    return CKIsGreaterThanOrEqualWithTolerance(sz.max.width, size.width)
+    && CKIsGreaterThanOrEqualWithTolerance(size.width, sz.min.width)
+    && CKIsGreaterThanOrEqualWithTolerance(sz.max.height,size.height)
+    && CKIsGreaterThanOrEqualWithTolerance(size.height,sz.min.height);
+}
+
+- (void)testExactMatch {
+    CKSizeRange sz(CGSizeMake(400, 400), CGSizeMake(400, 400));
+    CGSize s = CGSizeMake(400, 400);
+    XCTAssert(verifySizeRange(sz, s));
+}
+
+- (void)testRangeMatch {
+    CKSizeRange sz(CGSizeMake(0, 0), CGSizeMake(INFINITY, INFINITY));
+    CGSize s = CGSizeMake(400, 400);
+    XCTAssert(verifySizeRange(sz, s));
+}
+
+- (void)testNaNMatch {
+    CKSizeRange sz(CGSizeMake(NAN, NAN), CGSizeMake(NAN, NAN));
+    CGSize s = CGSizeMake(NAN, NAN);
+    XCTAssert(verifySizeRange(sz, s));
+}
+
+- (void)testVerySmallDifferenceMatch {
+    CKSizeRange sz(CGSizeMake(374.99999999999994, 400), CGSizeMake(374.99999999999994, 400));
+    CGSize s = CGSizeMake(375, 400);
+    XCTAssert(verifySizeRange(sz, s));
+}
+
+- (void)testVerySmallDifferenceRangeMatch {
+    CKSizeRange sz(CGSizeMake(0, 380), CGSizeMake(INFINITY, 400));
+    CGSize s = CGSizeMake(400, 379.99999999999994);
+    XCTAssert(verifySizeRange(sz, s));
+}
+
+@end