Match registered collection endpoints for resolution

internal/engine/resolution_correspondence_test.go

@@ -0,0 +1,65 @@
+package engine
+
+import "testing"
+
+func TestResolutionCollectionCorrespondence(t *testing.T) {
+	policy, diagnostics := compileSequenceIdentityPolicy([]sequenceIdentityRegistration{{
+		selector: sequenceIdentitySelector{literalSequenceSelector("items")}, identityFields: []string{"id"},
+	}})
+	if len(diagnostics) != 0 {
+		t.Fatal(diagnostics)
+	}
+	for _, test := range []struct {
+		name, before, after    string
+		eligible, structural   bool
+		finalIndex, entryIndex int
+		matched                bool
+	}{
+		{"swap", "items: [{id: a}, {id: b}]", "items: [{id: b}, {id: a}]", true, true, 0, 1, true},
+		{"insert", "items: [{id: a}]", "items: [{id: b}, {id: a}]", true, true, 0, 0, false},
+		{"remove", "items: [{id: a}, {id: b}]", "items: [{id: b}]", true, true, 0, 1, true},
+		{"same", "items: [{id: a}]", "items: [{id: a}]", true, false, 0, 0, true},
+		{"duplicate", "items: [{id: a}, {id: a}]", "items: [{id: a}]", false, false, 0, 0, true},
+		{"missing", "items: [{name: a}]", "items: [{id: a}]", false, false, 0, 0, true},
+		{"identity replacement", "items: [{id: a}]", "items: [{id: b}]", true, true, 0, 0, false},
+		{"invalid final", "items: [{id: a}]", "items: [bad]", false, false, 0, 0, true},
+	} {
+		t.Run(test.name, func(t *testing.T) {
+			before := parseCompositionDocument(t, "before", test.before)
+			after := parseCompositionDocument(t, "after", test.after)
+			matching := buildResolutionCorrespondence(before, after, policy)
+			collection := matching.collections["/items"]
+			if collection.eligible != test.eligible || collection.structural != test.structural {
+				t.Fatalf("collection = %#v", collection)
+			}
+			entry, ok := matching.entryPath(Keys("items").Index(test.finalIndex).Key("value"))
+			if ok != test.matched || (ok && entry.String() != Keys("items").Index(test.entryIndex).Key("value").String()) {
+				t.Fatalf("entry = %s, matched = %t", entry.String(), ok)
+			}
+		})
+	}
+}
+
+func TestResolutionCorrespondenceDynamicCompoundIdentities(t *testing.T) {
+	policy, diagnostics := compileSequenceIdentityPolicy([]sequenceIdentityRegistration{{
+		selector:       sequenceIdentitySelector{literalSequenceSelector("groups"), anyMappingSequenceSelector(), literalSequenceSelector("items")},
+		identityFields: []string{"id", "kind"},
+	}})
+	if len(diagnostics) != 0 {
+		t.Fatal(diagnostics)
+	}
+	before := parseCompositionDocument(t, "before", "groups: {alpha: {items: [{id: 1, kind: x}, {id: '1', kind: x}]}, empty: {items: []}}")
+	after := parseCompositionDocument(t, "after", "groups: {alpha: {items: [{id: '1', kind: x}, {id: 1.0, kind: x}]}, empty: {items: []}}")
+	matching := buildResolutionCorrespondence(before, after, policy)
+	if empty := matching.collections["/groups/empty/items"]; !empty.eligible || empty.structural {
+		t.Fatalf("empty = %#v", empty)
+	}
+	path, ok := matching.entryPath(Keys("groups", "alpha", "items").Index(0).Key("missing"))
+	if !ok || path.String() != "/groups/alpha/items/1/missing" {
+		t.Fatalf("entry = %s, %t", path.String(), ok)
+	}
+	wrongShape, ok := matching.entryPath(Keys("groups").Index(0).Key("items").Index(0))
+	if !ok || wrongShape.String() != "/groups/0/items/0" {
+		t.Fatalf("mapping shape = %s, %t", wrongShape.String(), ok)
+	}
+}