Stop using method swizzling for registering CurrentTestCaseTracker to…

… XCTestObservationCenter

The weird workaround is no longer needed in recent Xcode versions (at least Xcode 10.1 or later).

Sources/NimbleObjectiveC/XCTestObservationCenter+Register.m

@@ -1,83 +1,12 @@
 #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:));
-    }
+__attribute__((constructor))
+static void registerCurrentTestCaseTracker(void) {
+    [[XCTestObservationCenter sharedTestObservationCenter] addTestObserver:[CurrentTestCaseTracker sharedInstance]];
 }
-
-#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