refactor: improve code structure and add tests

gomockctx.go

@@ -4,8 +4,6 @@ package gomockctx
 
 import (
 	"context"
-	"fmt"
-	"reflect"
 
 	"github.com/golang/mock/gomock"
 )
@@ -15,76 +13,10 @@ type (
 	contextValue string
 )
 
-var ctxKey contextKey = "gomockctx context ID"
-
-// New returns a context as a child of the given parent, and with a randomized
-// gomockctx ID value set, making it a gomockctx context. This can then be used
-// with Is to get a gomock Matcher which returns true for the context from New,
-// or any child contexts of it.
-//
-// If crypto/rand returns an error, this will panic trying to generate the
-// gomockctx ID. In practise though, crypto/rand should never return a error.
-func New(parent context.Context) context.Context {
-	return context.WithValue(parent, ctxKey, newCtxID())
-}
-
-// Is accepts a context with a gomockctx ID value (as returned from New), and
-// returns a gomock.Matcher which returns true for the given context, of any
-// child contexts of it.
-//
-// If ctx was not returned from New, the resulting matcher will ALWAYS return
-// false.
-func Is(ctx context.Context) gomock.Matcher {
-	return WithValue(ctxKey, value(ctx))
-}
-
-// ID returns the gomockctx ID value in the given context, or a empty string if
-// the context does not have a gomockctx ID value.
-func ID(ctx context.Context) string {
-	if ctx == nil {
-		return ""
-	}
-
-	return string(value(ctx))
-}
-
-// Any returns a gomock.Matcher which matches any context.Context object.
-func Any() gomock.Matcher {
-	return gomock.AssignableToTypeOf(
-		reflect.TypeOf((*context.Context)(nil)).Elem(),
-	)
-}
-
-// WithValue returns a gomock.Matcher which matches any context that has the
-// specified key and value.
-func WithValue(key interface{}, value interface{}) gomock.Matcher {
-	return &contextMatcher{
-		key:   key,
-		value: value,
-	}
-}
-
-type contextMatcher struct {
-	key   interface{}
-	value interface{}
-}
-
-var _ gomock.Matcher = &contextMatcher{}
-
-func (cm *contextMatcher) Matches(x interface{}) bool {
-	if ctx, ok := x.(context.Context); ok {
-		return reflect.DeepEqual(cm.value, ctx.Value(cm.key))
-	}
-
-	return false
-}
-
-func (cm *contextMatcher) String() string {
-	return fmt.Sprintf(`context with "%+v" = "%+v"`, cm.key, cm.value)
-}
+var ctxKey contextKey = "gomockctx ID"
 
 func newCtxID() contextValue {
-	id, err := randString(64)
+	id, err := randString(32)
 	if err != nil {
 		panic(err)
 	}
@@ -92,7 +24,7 @@ func newCtxID() contextValue {
 	return contextValue(id)
 }
 
-func value(ctx context.Context) contextValue {
+func getValue(ctx context.Context) contextValue {
 	var value contextValue
 	if ctx == nil {
 		return value
@@ -105,3 +37,34 @@ func value(ctx context.Context) contextValue {
 
 	return value
 }
+
+// New returns a context as a child of the given parent, which includes a
+// randomized gomockctx ID value set, which makes it a gomockctx context. This
+// can then be used with Is to get a gomock Matcher which returns true for the
+// context from New, or any child contexts of it.
+//
+// If crypto/rand returns an error, this will panic trying to generate the
+// gomockctx ID. In practice though, crypto/rand should never return a error.
+func New(parent context.Context) context.Context {
+	return context.WithValue(parent, ctxKey, newCtxID())
+}
+
+// Is accepts a context with a gomockctx ID value (as returned from New), and
+// returns a gomock.Matcher which returns true for the given context, of any
+// child contexts of it.
+//
+// If ctx was not returned from New, the resulting matcher will ALWAYS return
+// false.
+func Is(ctx context.Context) gomock.Matcher {
+	return WithValue(ctxKey, getValue(ctx))
+}
+
+// ID returns the gomockctx ID value in the given context, or a empty string if
+// the context does not have a gomockctx ID value.
+func ID(ctx context.Context) string {
+	if ctx == nil {
+		return ""
+	}
+
+	return string(getValue(ctx))
+}