init iOS module

iOS/Example/Pods/Nimble/Sources/NimbleObjectiveC/XCTestObservationCenter+Register.m

@@ -0,0 +1,83 @@
+#import <XCTest/XCTest.h>
+#import <objc/runtime.h>
+
+#if __has_include("Nimble-Swift.h")
+#import "Nimble-Swift.h"
+#else
+#import <Nimble/Nimble-Swift.h>
+#endif
+
+#pragma mark - Method Swizzling
+
+/// Swaps the implementations between two instance methods.
+///
+/// @param class               The class containing `originalSelector`.
+/// @param originalSelector    Original method to replace.
+/// @param replacementSelector Replacement method.
+void swizzleSelectors(Class class, SEL originalSelector, SEL replacementSelector) {
+    Method originalMethod = class_getInstanceMethod(class, originalSelector);
+    Method replacementMethod = class_getInstanceMethod(class, replacementSelector);
+
+    BOOL didAddMethod =
+    class_addMethod(class,
+                    originalSelector,
+                    method_getImplementation(replacementMethod),
+                    method_getTypeEncoding(replacementMethod));
+
+    if (didAddMethod) {
+        class_replaceMethod(class,
+                            replacementSelector,
+                            method_getImplementation(originalMethod),
+                            method_getTypeEncoding(originalMethod));
+    } else {
+        method_exchangeImplementations(originalMethod, replacementMethod);
+    }
+}
+
+#pragma mark - Private
+
+@interface XCTestObservationCenter (Private)
+- (void)_addLegacyTestObserver:(id)observer;
+@end
+
+@implementation XCTestObservationCenter (Register)
+
+/// Uses objc method swizzling to register `CurrentTestCaseTracker` as a test observer. This is necessary
+/// because Xcode 7.3 introduced timing issues where if a custom `XCTestObservation` is registered too early
+/// it suppresses all console output (generated by `XCTestLog`), breaking any tools that depend on this output.
+/// This approach waits to register our custom test observer until XCTest adds its first "legacy" observer,
+/// falling back to registering after the first normal observer if this private method ever changes.
++ (void)load {
+    if (class_getInstanceMethod([self class], @selector(_addLegacyTestObserver:))) {
+        // Swizzle -_addLegacyTestObserver:
+        swizzleSelectors([self class], @selector(_addLegacyTestObserver:), @selector(NMB_original__addLegacyTestObserver:));
+    } else {
+        // Swizzle -addTestObserver:, only if -_addLegacyTestObserver: is not implemented
+        swizzleSelectors([self class], @selector(addTestObserver:), @selector(NMB_original_addTestObserver:));
+    }
+}
+
+#pragma mark - Replacement Methods
+
+/// Registers `CurrentTestCaseTracker` as a test observer after `XCTestLog` has been added.
+- (void)NMB_original__addLegacyTestObserver:(id)observer {
+    [self NMB_original__addLegacyTestObserver:observer];
+
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        [self addTestObserver:[CurrentTestCaseTracker sharedInstance]];
+    });
+}
+
+/// Registers `CurrentTestCaseTracker` as a test observer after `XCTestLog` has been added.
+/// This method is only used if `-_addLegacyTestObserver:` is not impelemented. (added in Xcode 7.3)
+- (void)NMB_original_addTestObserver:(id<XCTestObservation>)observer {
+    [self NMB_original_addTestObserver:observer];
+
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        [self NMB_original_addTestObserver:[CurrentTestCaseTracker sharedInstance]];
+    });
+}
+
+@end