refactor: improve code structure and add tests

gomockctx_test.go

@@ -2,11 +2,113 @@ package gomockctx
 
 import (
 	"context"
+	"regexp"
 	"testing"
 
+	"github.com/golang/mock/gomock"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
+func TestNew(t *testing.T) {
+	type key struct{}
+	k := key{}
+	ctxIDRegexp := regexp.MustCompile(`^[A-Za-z0-9]+$`)
+	parent := context.WithValue(context.Background(), k, "the parent")
+
+	ids := map[contextValue]struct{}{}
+	limit := 1000
+
+	for i := 0; i < limit; i++ {
+		ctx := New(parent)
+		require.Equal(t, "the parent", ctx.Value(k))
+
+		v := ctx.Value(ctxKey)
+		require.IsType(t, contextValue(""), v)
+		require.Len(t, v, 32)
+		require.Regexp(t, ctxIDRegexp, v)
+		cv, _ := v.(contextValue)
+		ids[cv] = struct{}{}
+	}
+
+	assert.Len(t, ids, limit)
+}
+
+func TestIs(t *testing.T) {
+	type strKey string
+
+	type args struct {
+		ctx context.Context
+	}
+	tests := []struct {
+		name string
+		args args
+		want *valueMatcher
+	}{
+		{
+			name: "nil",
+			args: args{
+				ctx: nil,
+			},
+			want: &valueMatcher{
+				key:   ctxKey,
+				value: contextValue(""),
+			},
+		},
+		{
+			name: "context without gomockctx ID",
+			args: args{
+				ctx: context.Background(),
+			},
+			want: &valueMatcher{
+				key:   ctxKey,
+				value: contextValue(""),
+			},
+		},
+		{
+			name: "context with gomockctx ID",
+			args: args{
+				ctx: context.WithValue(
+					context.Background(),
+					ctxKey,
+					contextValue("z9KZVcfmA4sWJX0yuIIESVcEARlwiAT2"),
+				),
+			},
+			want: &valueMatcher{
+				key:   ctxKey,
+				value: contextValue("z9KZVcfmA4sWJX0yuIIESVcEARlwiAT2"),
+			},
+		},
+		{
+			name: "child context of context with gomockctx ID",
+			args: args{
+				ctx: context.WithValue(
+					context.WithValue(
+						context.Background(),
+						ctxKey,
+						contextValue("hWEKf4Gtj15iLx4R7IFlHc5ooj5tU4UW"),
+					),
+					strKey("foo"),
+					"bar",
+				),
+			},
+			want: &valueMatcher{
+				key:   ctxKey,
+				value: contextValue("hWEKf4Gtj15iLx4R7IFlHc5ooj5tU4UW"),
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := Is(tt.args.ctx)
+
+			assert.Implements(t, (*gomock.Matcher)(nil), got)
+
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
 func TestID(t *testing.T) {
 	tests := []struct {
 		name string