Avoid testing global InstrumentationSystem state

Tests/TracingTests/ActorTracingTests.swift

@@ -18,12 +18,8 @@ import XCTest
 
 @testable import Instrumentation
 
+/// This is a compile-time test
 final class ActorTracingTests: XCTestCase {
-    override class func tearDown() {
-        super.tearDown()
-        InstrumentationSystem.bootstrapInternal(nil)
-    }
-
     func test() {}
 }
 

Tests/TracingTests/DynamicTracepointTracerTests.swift

@@ -19,19 +19,9 @@ import XCTest
 @testable import Instrumentation
 
 final class DynamicTracepointTracerTests: XCTestCase {
-    override class func tearDown() {
-        super.tearDown()
-        InstrumentationSystem.bootstrapInternal(nil)
-    }
-
     func test_adhoc_enableBySourceLoc() {
         let tracer = DynamicTracepointTestTracer()
 
-        InstrumentationSystem.bootstrapInternal(tracer)
-        defer {
-            InstrumentationSystem.bootstrapInternal(NoOpTracer())
-        }
-
         let fileID = #fileID
         let fakeLine: UInt = 77  // trick number, see withSpan below.
         let fakeNextLine: UInt = fakeLine + 11
@@ -71,19 +61,14 @@ final class DynamicTracepointTracerTests: XCTestCase {
     func test_adhoc_enableByFunction() {
         let tracer = DynamicTracepointTestTracer()
 
-        InstrumentationSystem.bootstrapInternal(tracer)
-        defer {
-            InstrumentationSystem.bootstrapInternal(NoOpTracer())
-        }
-
         let fileID = #fileID
-        tracer.enableTracepoint(function: "traceMeLogic(fakeLine:)")
+        tracer.enableTracepoint(function: "traceMeLogic(fakeLine:tracer:)")
 
         let fakeLine: UInt = 66
         let fakeNextLine: UInt = fakeLine + 11
 
-        self.logic(fakeLine: 55)
-        self.traceMeLogic(fakeLine: fakeLine)
+        self.logic(fakeLine: 55, tracer: tracer)
+        self.traceMeLogic(fakeLine: fakeLine, tracer: tracer)
 
         XCTAssertEqual(tracer.spans.count, 2)
         for span in tracer.spans {
@@ -93,15 +78,15 @@ final class DynamicTracepointTracerTests: XCTestCase {
         XCTAssertEqual(tracer.spans[1].context.spanID, "span-id-fake-\(fileID)-\(fakeNextLine)")
     }
 
-    func logic(fakeLine: UInt) {
-        InstrumentationSystem.tracer.withSpan("\(#function)-dont", line: fakeLine) { _ in
+    func logic(fakeLine: UInt, tracer: any Tracer) {
+        tracer.withSpan("\(#function)-dont", line: fakeLine) { _ in
             // inside
         }
     }
 
-    func traceMeLogic(fakeLine: UInt) {
-        InstrumentationSystem.tracer.withSpan("\(#function)-yes", line: fakeLine) { _ in
-            InstrumentationSystem.tracer.withSpan("\(#function)-yes-inside", line: fakeLine + 11) { _ in
+    func traceMeLogic(fakeLine: UInt, tracer: any Tracer) {
+        tracer.withSpan("\(#function)-yes", line: fakeLine) { _ in
+            tracer.withSpan("\(#function)-yes-inside", line: fakeLine + 11) { _ in
                 // inside
             }
         }

Tests/TracingTests/SpanTests.swift

@@ -82,7 +82,8 @@ final class SpanTests: XCTestCase {
     }
 
     func testSpanAttributeIsExpressibleByArrayLiteral() {
-        let s = InstrumentationSystem.legacyTracer.startAnySpan("", context: .topLevel)
+        let tracer = TestTracer()
+        let s = tracer.startAnySpan("", context: .topLevel)
         s.attributes["hi"] = [42, 21]
         s.attributes["hi"] = [42.10, 21.0]
         s.attributes["hi"] = [true, false]
@@ -91,12 +92,8 @@ final class SpanTests: XCTestCase {
     }
 
     func testSpanAttributeSetEntireCollection() {
-        InstrumentationSystem.bootstrapInternal(TestTracer())
-        defer {
-            InstrumentationSystem.bootstrapInternal(NoOpTracer())
-        }
-
-        let s = InstrumentationSystem.legacyTracer.startAnySpan("", context: .topLevel)
+        let tracer = TestTracer()
+        let s = tracer.startAnySpan("", context: .topLevel)
         var attrs = s.attributes
         attrs["one"] = 42
         attrs["two"] = [1, 2, 34]

Tests/TracingTests/TestTracer.swift

@@ -118,7 +118,7 @@ extension ServiceContext {
 
 /// Only intended to be used in single-threaded testing.
 final class TestSpan: Span {
-    private let kind: SpanKind
+    let kind: SpanKind
 
     private var status: SpanStatus?
 

Tests/TracingTests/TracedLock.swift

@@ -30,10 +30,10 @@ final class TracedLock: @unchecked Sendable {
         self.underlyingLock = NSLock()
     }
 
-    func lock(context: ServiceContext) {
+    func lock(context: ServiceContext, tracer: any Tracer) {
         // time here
         self.underlyingLock.lock()
-        self.activeSpan = InstrumentationSystem.legacyTracer.startAnySpan(self.name, context: context)
+        self.activeSpan = tracer.startSpan(self.name, context: context)
     }
 
     func unlock(context: ServiceContext) {
@@ -42,8 +42,8 @@ final class TracedLock: @unchecked Sendable {
         self.underlyingLock.unlock()
     }
 
-    func withLock(context: ServiceContext, _ closure: () -> Void) {
-        self.lock(context: context)
+    func withLock(context: ServiceContext, tracer: any Tracer, _ closure: () -> Void) {
+        self.lock(context: context, tracer: tracer)
         defer { self.unlock(context: context) }
         closure()
     }

Tests/TracingTests/TracedLockTests.swift

@@ -19,23 +19,16 @@ import XCTest
 @testable import Instrumentation
 
 final class TracedLockTests: XCTestCase {
-    override class func tearDown() {
-        super.tearDown()
-        InstrumentationSystem.bootstrapInternal(nil)
-    }
-
     func test_tracesLockedTime() {
         let tracer = TracedLockPrintlnTracer()
-        InstrumentationSystem.bootstrapInternal(tracer)
-
         let lock = TracedLock(name: "my-cool-lock")
 
         func launchTask(_ name: String) {
             DispatchQueue.global().async {
                 var context = ServiceContext.topLevel
                 context[TaskIDKey.self] = name
 
-                lock.lock(context: context)
+                lock.lock(context: context, tracer: tracer)
                 lock.unlock(context: context)
             }
         }