add tests to cover environment selection

extract a repoList interface to simplify tests

Signed-off-by: Yves Brissaud <yves@dagger.io>

Author: eunomie

cmd/cu/env.go

@@ -4,10 +4,14 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/dagger/container-use/repository"
+	"github.com/dagger/container-use/environment"
 )
 
-func envOrDefault(ctx context.Context, arg string, repo *repository.Repository) (string, error) {
+type repoLister interface {
+	List(ctx context.Context) ([]*environment.EnvironmentInfo, error)
+}
+
+func envOrDefault(ctx context.Context, arg string, repo repoLister) (string, error) {
 	if arg != "" {
 		return arg, nil
 	}

cmd/cu/env_test.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"context"
+	"testing"
+
+	"github.com/dagger/container-use/environment"
+)
+
+func TestEnvironmentFromArgs(t *testing.T) {
+	ctx := context.Background()
+	tests := []struct {
+		name          string
+		arg           string
+		repo          repoLister
+		expected      string
+		expectedError bool
+	}{
+		{
+			name:          "arg defined and not environments",
+			arg:           "fancy-mallard",
+			repo:          &repo{},
+			expected:      "fancy-mallard",
+			expectedError: false,
+		},
+		{
+			name: "arg defined and environments",
+			arg:  "fancy-mallard",
+			repo: &repo{
+				list: []*environment.EnvironmentInfo{
+					{ID: "foo"},
+					{ID: "bar"},
+				},
+			},
+			expected:      "fancy-mallard",
+			expectedError: false,
+		},
+		{
+			name:          "no arg, no environment",
+			arg:           "",
+			repo:          &repo{},
+			expected:      "",
+			expectedError: true,
+		},
+		{
+			name: "no arg, one environment",
+			arg:  "",
+			repo: &repo{
+				list: []*environment.EnvironmentInfo{
+					{ID: "fancy-mallard"},
+				},
+			},
+			expected:      "fancy-mallard",
+			expectedError: false,
+		},
+		{
+			name: "no arg, more than one environment",
+			arg:  "",
+			repo: &repo{
+				list: []*environment.EnvironmentInfo{
+					{ID: "fancy-mallard"},
+					{ID: "bar"},
+				},
+			},
+			expected:      "",
+			expectedError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			env, err := envOrDefault(ctx, tt.arg, tt.repo)
+			if (err != nil) != tt.expectedError {
+				t.Errorf("envOrDefault() error = %v, wantErr %v", err, tt.expectedError)
+				return
+			}
+			if env != tt.expected {
+				t.Errorf("envOrDefault() = %v, want %v", env, tt.expected)
+			}
+		})
+	}
+}
+
+type repo struct {
+	list []*environment.EnvironmentInfo
+}
+
+func (r *repo) List(_ context.Context) ([]*environment.EnvironmentInfo, error) {
+	return r.list, nil
+}