feat: validate specs before writing in simplebuild

We had an issue where invalid specs would be written if there were no
paths. We would not check what we were writing was invalid so it would
pass all CI checks then fail at runtime when something tried to use
them.

This patch ensures that will never happen by verifying what we write is
valid.

internal/simplebuild/build.go

@@ -97,7 +97,7 @@ func Build(
 				return err
 			}
 
-			err = writer.Write(doc)
+			err = writer.Write(ctx, doc)
 			if err != nil {
 				return err
 			}
@@ -153,7 +153,11 @@ func (ops Operations) Build(startVersion vervet.Version) DocSet {
 		output[idx] = VersionedDoc{
 			Doc: &openapi3.T{
 				OpenAPI: "3.0.3",
-				Paths:   openapi3.NewPaths(),
+				Info: &openapi3.Info{
+					Title:   "Snyk API",
+					Version: "1.0.0",
+				},
+				Paths: openapi3.NewPaths(),
 			},
 			VersionDate: versionDate,
 		}

internal/simplebuild/output.go

@@ -1,6 +1,7 @@
 package simplebuild
 
 import (
+	"context"
 	"fmt"
 	"io/fs"
 	"os"
@@ -59,13 +60,18 @@ func NewWriter(cfg config.Output, appendOutputFiles bool) (*DocWriter, error) {
 
 // Write writes compiled specs to a single directory in YAML and JSON formats.
 // Call Finalize after to populate other directories.
-func (out *DocWriter) Write(doc VersionedDoc) error {
+func (out *DocWriter) Write(ctx context.Context, doc VersionedDoc) error {
+	err := doc.Doc.Validate(ctx)
+	if err != nil {
+		return fmt.Errorf("invalid compiled document: %w", err)
+	}
+
 	// We write to the first directory then copy the entire directory
 	// afterwards
 	dir := out.paths[0]
 
 	versionDir := path.Join(dir, doc.VersionDate.Format(time.DateOnly))
-	err := os.MkdirAll(versionDir, 0755)
+	err = os.MkdirAll(versionDir, 0755)
 	if err != nil {
 		return fmt.Errorf("make output directory: %w", err)
 	}

internal/simplebuild/output_test.go

@@ -1,6 +1,7 @@
 package simplebuild
 
 import (
+	"context"
 	"os"
 	"path"
 	"path/filepath"
@@ -123,14 +124,15 @@ func TestDocSet_WriteOutputs(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
 			if tt.setup != nil {
 				tt.setup(t, tt.args)
 			}
 
 			writer, err := NewWriter(tt.args.cfg, tt.args.appendOutputFiles)
 			c.Assert(err, qt.IsNil)
 			for _, doc := range tt.docs {
-				err = writer.Write(doc)
+				err = writer.Write(ctx, doc)
 				c.Assert(err, qt.IsNil)
 			}
 			err = writer.Finalize()
@@ -142,4 +144,8 @@ func TestDocSet_WriteOutputs(t *testing.T) {
 }
 
 var minimalSpec = `---
+openapi: 3.0.3
+info:
+  title: minimal spec
+  version: 1.0.0
 paths: {}`