Add test for potential namespace

Test verifies that potential namespace is stored in database and it can
be loaded back to structure.

The commit also fixes few typos and bugs.

database/dbutil.go

@@ -60,7 +60,7 @@ func ConvertFeatureSetToFeatures(features mapset.Set) []Feature {
 	return uniqueFeatures
 }
 
-func ConvertFeatureSerToLayerFeatures(features mapset.Set) []LayerFeature {
+func ConvertFeatureSetToLayerFeatures(features mapset.Set) []LayerFeature {
 	uniqueLayerFeatures := make([]LayerFeature, 0, features.Cardinality())
 	for f := range features.Iter() {
 		feature := f.(Feature)

database/pgsql/layer.go

@@ -37,12 +37,15 @@ const (
 		SELECT id FROM layer WHERE hash = $1`
 
 	findLayerFeatures = `
-		SELECT f.name, f.version, f.version_format, t.name, lf.detector_id, ns.name, ns.version_format
-			FROM layer_feature AS lf, feature AS f, feature_type AS t, namespace AS ns
-			WHERE lf.feature_id = f.id
-				AND t.id = f.type
-				AND lf.namespace_id = ns.id
-				AND lf.layer_id = $1`
+		SELECT
+			f.name, f.version, f.version_format, ft.name, lf.detector_id, ns.name, ns.version_format
+		FROM
+			layer_feature AS lf
+		LEFT JOIN feature f on f.id = lf.feature_id
+		LEFT JOIN feature_type ft on ft.id = f.type
+		LEFT JOIN namespace ns ON ns.id = lf.namespace_id
+
+		WHERE lf.layer_id = $1`
 
 	findLayerNamespaces = `
 		SELECT ns.name, ns.version_format, ln.detector_id
@@ -320,9 +323,12 @@ func (tx *pgSession) findLayerFeatures(layerID int64, detectors detectorMap) ([]
 			detectorID int64
 			feature    database.LayerFeature
 		)
-		if err := rows.Scan(&feature.Name, &feature.Version, &feature.VersionFormat, &feature.Type, &detectorID, &feature.PotentialNamespace.Name, &feature.PotentialNamespace.VersionFormat); err != nil {
+		var namespaceName, namespaceVersion sql.NullString
+		if err := rows.Scan(&feature.Name, &feature.Version, &feature.VersionFormat, &feature.Type, &detectorID, &namespaceName, &namespaceVersion); err != nil {
 			return nil, handleError("findLayerFeatures", err)
 		}
+		feature.PotentialNamespace.Name = namespaceName.String
+		feature.PotentialNamespace.VersionFormat = namespaceVersion.String
 
 		feature.By = detectors.byID[detectorID]
 		features = append(features, feature)

database/pgsql/layer_test.go

@@ -116,6 +116,28 @@ var persistLayerTests = []struct {
 			},
 		},
 	},
+
+	{
+		title: "layer with potential namespace",
+		name:  "layer-potential-namespace",
+		by:    []database.Detector{realDetectors[3]},
+		features: []database.LayerFeature{
+			{realFeatures[4], realDetectors[3], realNamespaces[4]},
+		},
+		namespaces: []database.LayerNamespace{
+			{realNamespaces[3], realDetectors[3]},
+		},
+		layer: &database.Layer{
+			Hash: "layer-potential-namespace",
+			By:   []database.Detector{realDetectors[3]},
+			Features: []database.LayerFeature{
+				{realFeatures[4], realDetectors[3], realNamespaces[4]},
+			},
+			Namespaces: []database.LayerNamespace{
+				{realNamespaces[3], realDetectors[3]},
+			},
+		},
+	},
 }
 
 func TestPersistLayer(t *testing.T) {

database/pgsql/migrations/00001_initial_schema.go

@@ -89,7 +89,7 @@ var (
 				layer_id INT REFERENCES layer ON DELETE CASCADE, 
 				feature_id INT REFERENCES feature ON DELETE CASCADE,
 				detector_id INT REFERENCES detector ON DELETE CASCADE,
-				namespace_id INT REFERENCES namespace ON DELETE CASCADE,
+				namespace_id INT NULL REFERENCES namespace ON DELETE CASCADE,
 				UNIQUE (layer_id, feature_id, namespace_id));`,
 			`CREATE INDEX ON layer_feature(layer_id);`,
 

database/pgsql/testdata/data.sql

@@ -2,7 +2,8 @@
 INSERT INTO namespace (id, name, version_format) VALUES
   (1, 'debian:7', 'dpkg'),
   (2, 'debian:8', 'dpkg'),
-  (3, 'fake:1.0', 'rpm');
+  (3, 'fake:1.0', 'rpm'),
+  (4, 'cpe:/o:redhat:enterprise_linux:7::server', 'rpm');
 
 INSERT INTO feature (id, name, version, version_format, type) VALUES
   (1, 'ourchat', '0.5', 'dpkg', 1),

database/pgsql/testutil.go

@@ -49,6 +49,7 @@ var (
 		1: {"debian:7", "dpkg"},
 		2: {"debian:8", "dpkg"},
 		3: {"fake:1.0", "rpm"},
+		4: {"cpe:/o:redhat:enterprise_linux:7::server", "rpm"},
 	}
 
 	realNamespacedFeatures = map[int]database.NamespacedFeature{

ext/featurefmt/apk/apk.go

@@ -86,7 +86,7 @@ func (l lister) ListFeatures(files tarutil.FilesMap) ([]database.LayerFeature, e
 		packages.Add(pkg)
 	}
 
-	return database.ConvertFeatureSerToLayerFeatures(packages), nil
+	return database.ConvertFeatureSetToLayerFeatures(packages), nil
 }
 
 func (l lister) RequiredFilenames() []string {

ext/featurefmt/dpkg/dpkg.go

@@ -69,7 +69,7 @@ func (l lister) ListFeatures(files tarutil.FilesMap) ([]database.LayerFeature, e
 		}
 	}
 
-	return database.ConvertFeatureSerToLayerFeatures(packages), nil
+	return database.ConvertFeatureSetToLayerFeatures(packages), nil
 }
 
 // parseDpkgDB consumes the status file scanner exactly one package info, until

ext/featurefmt/rpm/rpm.go

@@ -101,7 +101,7 @@ func (l lister) ListFeatures(files tarutil.FilesMap) ([]database.LayerFeature, e
 		}
 	}
 
-	return database.ConvertFeatureSerToLayerFeatures(packages), nil
+	return database.ConvertFeatureSetToLayerFeatures(packages), nil
 }
 
 func parseRPMOutput(raw string) (rpmPackage *database.Feature, srpmPackage *database.Feature) {