Decouple use of otel/internal/internaltest (open-telemetry#4424)

* Add internaltest templates

* Generate internaltest using gotmpl

* Generate the sdk/internal/internaltest pkg

* Use sdk/internal/internaltest in sdk module

* Generate exporters/jaeger/internal/internaltest pkg

* Use exporters/jaeger/internal/internaltest in jaeger exporter

* Generate the exporters/zipkin/internal/internaltest pkg

* Use local internaltest in zipkin exporter

* Fix import path name in trace test

exporters/jaeger/env_test.go

@@ -21,7 +21,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	ottest "go.opentelemetry.io/otel/internal/internaltest"
+	ottest "go.opentelemetry.io/otel/exporters/jaeger/internal/internaltest"
 )
 
 func TestNewRawExporterWithDefault(t *testing.T) {

exporters/jaeger/internal/internaltest/alignment.go

@@ -0,0 +1,74 @@
+// Code created by gotmpl. DO NOT MODIFY.
+// source: internal/shared/internaltest/alignment.go.tmpl
+
+// 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 internaltest // import "go.opentelemetry.io/otel/exporters/jaeger/internal/internaltest"
+
+/*
+This file contains common utilities and objects to validate memory alignment
+of Go types. The primary use of this functionality is intended to ensure
+`struct` fields that need to be 64-bit aligned so they can be passed as
+arguments to 64-bit atomic operations.
+
+The common workflow is to define a slice of `FieldOffset` and pass them to the
+`Aligned8Byte` function from within a `TestMain` function from a package's
+tests. It is important to make this call from the `TestMain` function prior
+to running the rest of the test suit as it can provide useful diagnostics
+about field alignment instead of ambiguous nil pointer dereference and runtime
+panic.
+
+For more information:
+https://github.com/open-telemetry/opentelemetry-go/issues/341
+*/
+
+import (
+	"fmt"
+	"io"
+)
+
+// FieldOffset is a preprocessor representation of a struct field alignment.
+type FieldOffset struct {
+	// Name of the field.
+	Name string
+
+	// Offset of the field in bytes.
+	//
+	// To compute this at compile time use unsafe.Offsetof.
+	Offset uintptr
+}
+
+// Aligned8Byte returns if all fields are aligned modulo 8-bytes.
+//
+// Error messaging is printed to out for any field determined misaligned.
+func Aligned8Byte(fields []FieldOffset, out io.Writer) bool {
+	misaligned := make([]FieldOffset, 0)
+	for _, f := range fields {
+		if f.Offset%8 != 0 {
+			misaligned = append(misaligned, f)
+		}
+	}
+
+	if len(misaligned) == 0 {
+		return true
+	}
+
+	fmt.Fprintln(out, "struct fields not aligned for 64-bit atomic operations:")
+	for _, f := range misaligned {
+		fmt.Fprintf(out, "  %s: %d-byte offset\n", f.Name, f.Offset)
+	}
+
+	return false
+}

exporters/jaeger/internal/internaltest/env.go

@@ -0,0 +1,101 @@
+// Code created by gotmpl. DO NOT MODIFY.
+// source: internal/shared/internaltest/env.go.tmpl
+
+// 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 internaltest // import "go.opentelemetry.io/otel/exporters/jaeger/internal/internaltest"
+
+import (
+	"os"
+)
+
+type Env struct {
+	Name   string
+	Value  string
+	Exists bool
+}
+
+// EnvStore stores and recovers environment variables.
+type EnvStore interface {
+	// Records the environment variable into the store.
+	Record(key string)
+
+	// Restore recovers the environment variables in the store.
+	Restore() error
+}
+
+var _ EnvStore = (*envStore)(nil)
+
+type envStore struct {
+	store map[string]Env
+}
+
+func (s *envStore) add(env Env) {
+	s.store[env.Name] = env
+}
+
+func (s *envStore) Restore() error {
+	var err error
+	for _, v := range s.store {
+		if v.Exists {
+			err = os.Setenv(v.Name, v.Value)
+		} else {
+			err = os.Unsetenv(v.Name)
+		}
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (s *envStore) setEnv(key, value string) error {
+	s.Record(key)
+
+	err := os.Setenv(key, value)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (s *envStore) Record(key string) {
+	originValue, exists := os.LookupEnv(key)
+	s.add(Env{
+		Name:   key,
+		Value:  originValue,
+		Exists: exists,
+	})
+}
+
+func NewEnvStore() EnvStore {
+	return newEnvStore()
+}
+
+func newEnvStore() *envStore {
+	return &envStore{store: make(map[string]Env)}
+}
+
+func SetEnvVariables(env map[string]string) (EnvStore, error) {
+	envStore := newEnvStore()
+
+	for k, v := range env {
+		err := envStore.setEnv(k, v)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return envStore, nil
+}