test: Fix flaky SentryThreadInspectorTests (#5819)

Change the assertion approach of
testGetCurrentThreadsWithStacktrace_WithSymbolication and
testGetCurrentThreadsWithStacktrace_WithoutSymbolication to validate
the percentage of threads having a stracktrace, which is more robust
than the previous method which failed if more than one thread had no
stacktrace frames. Especially during the test when launching multiple
threads for the concurrent DispatchQueue it can occur that more than
one thread have no stacktrace frames yet, because they just started.

Author: philipphofmann

Tests/SentryTests/SentryCrash/SentryThreadInspectorTests.swift

@@ -1,3 +1,4 @@
+@_spi(Private) @testable import Sentry
 import SentryTestUtils
 import XCTest
 
@@ -54,32 +55,45 @@ class SentryThreadInspectorTests: XCTestCase {
         expect.expectedFulfillmentCount = 10
 
         let sut = self.fixture.getSut(testWithRealMachineContextWrapper: true)
+
         for _ in 0..<10 {
-            
+
             queue.async {
-                let actual = sut.getCurrentThreadsWithStackTrace()
-                
-                // Sometimes during tests its possible to have one thread without frames
-                // We just need to make sure we retrieve frame information for at least one other thread than the main thread
-                var threadsWithFrames = 0
-                
-                for thr in actual {
-                    if (thr.stacktrace?.frames.count ?? 0) >= 1 {
-                        threadsWithFrames += 1
+                let threads = sut.getCurrentThreadsWithStackTrace()
+
+                var threadsWithStackTraceFrames = 0
+
+                for thread in threads {
+
+                    guard let frames = thread.stacktrace?.frames else {
+                        continue
+                    }
+
+                    if frames.count == 0 {
+                        continue
                     }
-                    
-                    for frame in thr.stacktrace?.frames ?? [] {
+
+                    for frame in frames {
                         XCTAssertNotNil(frame.instructionAddress)
                         XCTAssertNotNil(frame.imageAddress)
+
                     }
+
+                    threadsWithStackTraceFrames += 1
                 }
-                
-                XCTAssertTrue(threadsWithFrames > 1, "Not enough threads with frames")
-                
+
+                let percantageWithStacktraceFrames = Double(threadsWithStackTraceFrames) / Double(threads.count)
+
+                // During testing we usually have around 90% to 100%
+                // We choose a bit lower threshold to avoid flaky tests in CI
+                // Especially during the test when launching multiple threads for the concurrent DispatchQueue
+                // it can occur that more than one thread have no stacktrace frames yet, because they just started.
+                XCTAssertGreaterThan(percantageWithStacktraceFrames, 0.6, "More than 60% of threads should have stacktrace frames, but got \(percantageWithStacktraceFrames * 100)%")
+
                 expect.fulfill()
             }
         }
-        
+
         queue.activate()
         wait(for: [expect], timeout: 10)
     }
@@ -91,34 +105,45 @@ class SentryThreadInspectorTests: XCTestCase {
         expect.expectedFulfillmentCount = 10
 
         let sut = self.fixture.getSut(testWithRealMachineContextWrapper: true, symbolicate: false)
-        
+
         for _ in 0..<10 {
 
             queue.async {
-                let actual = sut.getCurrentThreadsWithStackTrace()
-                
-                // Sometimes during tests its possible to have one thread without frames
-                // We just need to make sure we retrieve frame information for at least one other thread than the main thread
-                var threadsWithFrames = 0
-                
-                for thr in actual {
-                    if (thr.stacktrace?.frames.count ?? 0) >= 1 {
-                        threadsWithFrames += 1
+                let threads = sut.getCurrentThreadsWithStackTrace()
+
+                var threadsWithStackTraceFrames = 0
+
+                for thread in threads {
+
+                    guard let frames = thread.stacktrace?.frames else {
+                        continue
+                    }
+
+                    if frames.count == 0 {
+                        continue
                     }
-                    
-                    for frame in thr.stacktrace?.frames ?? [] {
+
+                    for frame in frames {
                         XCTAssertNotNil(frame.instructionAddress)
                         XCTAssertNotNil(frame.imageAddress)
                         XCTAssertNil(frame.symbolAddress)
                     }
+
+                    threadsWithStackTraceFrames += 1
                 }
-                
-                XCTAssertTrue(threadsWithFrames > 1, "Not enough threads with frames")
-                
+
+                let percantageWithStacktraceFrames = Double(threadsWithStackTraceFrames) / Double(threads.count)
+
+                // During testing we usually have around 90% to 100%
+                // We choose a bit lower threshold to avoid flaky tests in CI
+                // Especially during the test when launching multiple threads for the concurrent DispatchQueue
+                // it can occur that more than one thread have no stacktrace frames yet, because they just started.
+                XCTAssertGreaterThan(percantageWithStacktraceFrames, 0.6, "More than 60% of threads should have stacktrace frames, but got \(percantageWithStacktraceFrames * 100)%")
+
                 expect.fulfill()
             }
         }
-        
+
         queue.activate()
         wait(for: [expect], timeout: 10)
     }