add sbom document import lib helper function

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

test/integration/document_import_test.go

@@ -0,0 +1,92 @@
+package integration
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/anchore/stereoscope/pkg/imagetest"
+	"github.com/anchore/syft/syft"
+	"github.com/anchore/syft/syft/pkg"
+	"github.com/anchore/syft/syft/presenter/json"
+	"github.com/anchore/syft/syft/scope"
+	"github.com/go-test/deep"
+)
+
+func TestCatalogFromJSON(t *testing.T) {
+
+	// ensure each of our fixture images results in roughly the same shape when:
+	//     generate json -> import json -> assert packages and distro are the same (except for select fields)
+
+	tests := []struct {
+		fixture string
+	}{
+		{
+			fixture: "image-pkg-coverage",
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.fixture, func(t *testing.T) {
+			_, cleanup := imagetest.GetFixtureImage(t, "docker-archive", test.fixture)
+			tarPath := imagetest.GetFixtureImageTarPath(t, test.fixture)
+			defer cleanup()
+
+			expectedCatalog, s, expectedDistro, err := syft.Catalog("docker-archive:"+tarPath, scope.AllLayersScope)
+			if err != nil {
+				t.Fatalf("failed to catalog image: %+v", err)
+			}
+
+			var buf bytes.Buffer
+			jsonPres := json.NewPresenter(expectedCatalog, *s, *expectedDistro)
+			if err = jsonPres.Present(&buf); err != nil {
+				t.Fatalf("failed to write to presenter: %+v", err)
+			}
+
+			// TODO: test img
+
+			actualCatalog, actualDistro, err := syft.CatalogFromJSON(&buf)
+			if err != nil {
+				t.Fatalf("failed to import document: %+v", err)
+			}
+
+			for _, d := range deep.Equal(actualDistro, expectedDistro) {
+				t.Errorf("   distro diff: %+v", d)
+			}
+
+			var actualPackages, expectedPackages []*pkg.Package
+
+			// TODO: take out pkg.RpmdbMetadataType filter
+
+			for _, p := range expectedCatalog.Sorted() {
+				expectedPackages = append(expectedPackages, p)
+			}
+
+			for _, p := range actualCatalog.Sorted() {
+				actualPackages = append(actualPackages, p)
+			}
+
+			if len(actualPackages) != len(expectedPackages) {
+				t.Fatalf("mismatched package length: %d != %d", len(actualPackages), len(expectedPackages))
+			}
+
+			for i, e := range expectedPackages {
+				a := actualPackages[i]
+
+				// omit fields that should be missing
+				e.Source = nil
+				e.FoundBy = ""
+				if e.MetadataType == pkg.JavaMetadataType {
+					metadata := e.Metadata.(pkg.JavaMetadata)
+					metadata.Parent = nil
+					e.Metadata = metadata
+				}
+
+				for _, d := range deep.Equal(a, e) {
+					t.Errorf("   package %d (name=%s) diff: %+v", i, e.Name, d)
+				}
+			}
+
+		})
+	}
+
+}