e2etests-cli: Add PNG test

Closes terrastruct#903
Closes terrastruct#918

d2cli/main.go

@@ -152,6 +152,8 @@ func Run(ctx context.Context, ms *xmain.State) (err error) {
 			outputPath = renameExt(inputPath, ".svg")
 		}
 	}
+	inputPath = filepath.Join(ms.PWD, inputPath)
+	outputPath = filepath.Join(ms.PWD, outputPath)
 
 	match := d2themescatalog.Find(*themeFlag)
 	if match == (d2themes.Theme{}) {

e2etests-cli/main_test.go

@@ -2,20 +2,32 @@ package e2etests_cli
 
 import (
 	"context"
+	"path/filepath"
 	"testing"
 	"time"
+
+	"oss.terrastruct.com/d2/d2cli"
+	"oss.terrastruct.com/util-go/assert"
+	"oss.terrastruct.com/util-go/xmain"
+	"oss.terrastruct.com/util-go/xos"
 )
 
 func TestCLI_E2E(t *testing.T) {
 	t.Parallel()
 
 	tca := []struct {
 		name string
-		run  func(t *testing.T, ctx context.Context)
+		run  func(t *testing.T, ctx context.Context, dir string, env *xos.Env)
 	}{
 		{
 			name: "hello_world",
-			run:  func(t *testing.T, ctx context.Context) {},
+			run: func(t *testing.T, ctx context.Context, dir string, env *xos.Env) {
+				assert.WriteFile(t, filepath.Join(dir, "hello-world.d2"), []byte(`x -> y`), 0644)
+				err := runTestMain(t, ctx, dir, env, "hello-world.d2",  "hello-world.png")
+				assert.Success(t, err)
+				png := assert.ReadFile(t, filepath.Join(dir, "hello-world.png"))
+				assert.Testdata(t, ".png", png)
+			},
 		},
 	}
 
@@ -28,7 +40,30 @@ func TestCLI_E2E(t *testing.T) {
 			ctx, cancel := context.WithTimeout(ctx, time.Minute*5)
 			defer cancel()
 
-			tc.run(t, ctx)
+			dir, cleanup := assert.TempDir(t)
+			defer cleanup()
+
+			env := xos.NewEnv(nil)
+
+			tc.run(t, ctx, dir, env)
 		})
 	}
 }
+
+// We do not run the CLI in its own process even though that makes it not truly e2e to
+// test whether we're cleaning up state correctly.
+func testMain(dir string, env *xos.Env, args ...string) *xmain.TestState {
+	return &xmain.TestState{
+		Run:  d2cli.Run,
+		Env:  env,
+		Args: append([]string{"e2etests-cli/d2"}, args...),
+		PWD:  dir,
+	}
+}
+
+func runTestMain(tb testing.TB, ctx context.Context, dir string, env *xos.Env, args ...string) error {
+	tms := testMain(dir, env, args...)
+	tms.Start(tb, ctx)
+	defer tms.Cleanup(tb)
+	return tms.Wait(ctx)
+}