diff --git a/api/global/internal/propagator_test.go b/api/global/internal/propagator_test.go
new file mode 100644
index 00000000000..4500df89f43
--- /dev/null
+++ b/api/global/internal/propagator_test.go
@@ -0,0 +1,108 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal_test
+
+import (
+	"context"
+	"testing"
+
+	"go.opentelemetry.io/otel/api/global/internal"
+	"go.opentelemetry.io/otel/oteltest"
+)
+
+func TestTextMapPropagatorDelegation(t *testing.T) {
+	internal.ResetForTest()
+	ctx := context.Background()
+	carrier := oteltest.NewTextMapCarrier(nil)
+
+	// The default should be a noop.
+	initial := internal.TextMapPropagator()
+	initial.Inject(ctx, carrier)
+	ctx = initial.Extract(ctx, carrier)
+	if !carrier.GotN(t, 0) || !carrier.SetN(t, 0) {
+		return
+	}
+
+	// Make sure the delegate woks as expected.
+	delegate := oteltest.NewTextMapPropagator("test")
+	delegate.Inject(ctx, carrier)
+	ctx = delegate.Extract(ctx, carrier)
+	if !delegate.InjectedN(t, carrier, 1) || !delegate.ExtractedN(t, ctx, 1) {
+		return
+	}
+
+	// The initial propagator should use the delegate after it is set as the
+	// global.
+	internal.SetTextMapPropagator(delegate)
+	initial.Inject(ctx, carrier)
+	ctx = initial.Extract(ctx, carrier)
+	delegate.InjectedN(t, carrier, 2)
+	delegate.ExtractedN(t, ctx, 2)
+}
+
+func TestTextMapPropagatorDelegationNil(t *testing.T) {
+	internal.ResetForTest()
+	ctx := context.Background()
+	carrier := oteltest.NewTextMapCarrier(nil)
+
+	// The default should be a noop.
+	initial := internal.TextMapPropagator()
+	initial.Inject(ctx, carrier)
+	ctx = initial.Extract(ctx, carrier)
+	if !carrier.GotN(t, 0) || !carrier.SetN(t, 0) {
+		return
+	}
+
+	// Delegation to nil should not make a change.
+	internal.SetTextMapPropagator(nil)
+	initial.Inject(ctx, carrier)
+	initial.Extract(ctx, carrier)
+	if !carrier.GotN(t, 0) || !carrier.SetN(t, 0) {
+		return
+	}
+}
+
+func TestTextMapPropagatorFields(t *testing.T) {
+	internal.ResetForTest()
+	initial := internal.TextMapPropagator()
+	delegate := oteltest.NewTextMapPropagator("test")
+	delegateFields := delegate.Fields()
+
+	// Sanity check on the initial Fields.
+	if got := initial.Fields(); fieldsEqual(got, delegateFields) {
+		t.Fatalf("testing fields (%v) matched Noop fields (%v)", delegateFields, got)
+	}
+	internal.SetTextMapPropagator(delegate)
+	// Check previous returns from global not correctly delegate.
+	if got := initial.Fields(); !fieldsEqual(got, delegateFields) {
+		t.Errorf("global TextMapPropagator.Fields returned %v instead of delegating, want (%v)", got, delegateFields)
+	}
+	// Check new calls to global.
+	if got := internal.TextMapPropagator().Fields(); !fieldsEqual(got, delegateFields) {
+		t.Errorf("global TextMapPropagator.Fields returned %v, want (%v)", got, delegateFields)
+	}
+}
+
+func fieldsEqual(f1, f2 []string) bool {
+	if len(f1) != len(f2) {
+		return false
+	}
+	for i := range f1 {
+		if f1[i] != f2[i] {
+			return false
+		}
+	}
+	return true
+}
diff --git a/api/global/internal/state.go b/api/global/internal/state.go
index 9542e60bf98..f7c467fe27c 100644
--- a/api/global/internal/state.go
+++ b/api/global/internal/state.go
@@ -138,4 +138,5 @@ func ResetForTest() {
 	globalPropagators = defaultPropagatorsValue()
 	delegateMeterOnce = sync.Once{}
 	delegateTraceOnce = sync.Once{}
+	delegateTextMapPropagatorOnce = sync.Once{}
 }
diff --git a/api/global/internal/state_test.go b/api/global/internal/state_test.go
new file mode 100644
index 00000000000..704e3782a22
--- /dev/null
+++ b/api/global/internal/state_test.go
@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package internal_test
+
+import (
+	"testing"
+
+	"go.opentelemetry.io/otel/api/global/internal"
+)
+
+func TestResetsOfGlobalsPanic(t *testing.T) {
+	internal.ResetForTest()
+	tests := map[string]func(){
+		"SetTextMapPropagator": func() {
+			internal.SetTextMapPropagator(internal.TextMapPropagator())
+		},
+		"SetTracerProvider": func() {
+			internal.SetTracerProvider(internal.TracerProvider())
+		},
+		"SetMeterProvider": func() {
+			internal.SetMeterProvider(internal.MeterProvider())
+		},
+	}
+
+	for name, test := range tests {
+		shouldPanic(t, name, test)
+	}
+}
+
+func shouldPanic(t *testing.T, name string, f func()) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("calling %s with default global did not panic", name)
+		}
+	}()
+
+	f()
+}
diff --git a/oteltest/text_map_propagator.go b/oteltest/text_map_propagator.go
index 320282a8e4b..b18919fac9b 100644
--- a/oteltest/text_map_propagator.go
+++ b/oteltest/text_map_propagator.go
@@ -111,7 +111,7 @@ func (c *TextMapCarrier) SetN(t *testing.T, n int) bool {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 	if len(c.sets) != n {
-		t.Errorf("TextMapCarrier.Set was called %d times, not %d", len(c.gets), n)
+		t.Errorf("TextMapCarrier.Set was called %d times, not %d", len(c.sets), n)
 		return false
 	}
 	return true