test: improve render coverage from 78.5% to 84.4%

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
         run: |
           total=$(go tool cover -func=coverage.out | awk '/^total:/ {gsub("%","",$3); print $3}')
           # Current enforced coverage floor. Codex PRs raise this incrementally toward 90%.
-          min=45.0
+          min=50.0
           awk -v t="$total" -v m="$min" 'BEGIN {
             if (t+0 < m+0) {
               printf "Coverage %.1f%% is below floor %.1f%%\n", t, m

render/depgraph_test.go

@@ -2,6 +2,8 @@ package render
 
 import (
 	"bytes"
+	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 
@@ -103,3 +105,73 @@ func TestDepgraphRendersExternalDepsAndSummarySection(t *testing.T) {
 		}
 	}
 }
+
+func writeDepgraphFixture(t *testing.T, root string) {
+	t.Helper()
+
+	files := map[string]string{
+		"go.mod":                "module example.com/demo\n\ngo 1.24.0\n",
+		"app/main.go":           "package app\n\nimport (\n\t\"example.com/demo/core/extra1\"\n\t\"example.com/demo/core/extra2\"\n\t\"example.com/demo/core/leaf\"\n\t\"example.com/demo/core/mid\"\n\t\"example.com/demo/core/root\"\n)\n\nfunc Main() {\n\textra1.Extra1()\n\textra2.Extra2()\n\tleaf.Leaf()\n\tmid.Mid()\n\troot.Root()\n}\n",
+		"core/root/root.go":     "package root\n\nimport \"example.com/demo/core/mid\"\n\nfunc Root() {\n\tmid.Mid()\n}\n",
+		"core/mid/mid.go":       "package mid\n\nimport \"example.com/demo/core/leaf\"\n\nfunc Mid() {\n\tleaf.Leaf()\n}\n",
+		"core/leaf/leaf.go":     "package leaf\n\nfunc Leaf() {}\n",
+		"core/extra1/extra1.go": "package extra1\n\nimport \"example.com/demo/core/leaf\"\n\nfunc Extra1() {\n\tleaf.Leaf()\n}\n",
+		"core/extra2/extra2.go": "package extra2\n\nimport \"example.com/demo/core/leaf\"\n\nfunc Extra2() {\n\tleaf.Leaf()\n}\n",
+	}
+
+	for path, content := range files {
+		full := filepath.Join(root, path)
+		if err := os.MkdirAll(filepath.Dir(full), 0o755); err != nil {
+			t.Fatal(err)
+		}
+		if err := os.WriteFile(full, []byte(content), 0o644); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestDepgraphRendersChainsFanoutAndHubs(t *testing.T) {
+	if !scanner.NewAstGrepAnalyzer().Available() {
+		t.Skip("ast-grep not available")
+	}
+
+	root := t.TempDir()
+	writeDepgraphFixture(t, root)
+
+	project := scanner.DepsProject{
+		Root: root,
+		Files: []scanner.FileAnalysis{
+			{Path: "app/main.go", Functions: []string{"Main"}},
+			{Path: "core/root/root.go", Functions: []string{"Root"}},
+			{Path: "core/mid/mid.go", Functions: []string{"Mid"}},
+			{Path: "core/leaf/leaf.go", Functions: []string{"Leaf"}},
+			{Path: "core/extra1/extra1.go", Functions: []string{"Extra1"}},
+			{Path: "core/extra2/extra2.go", Functions: []string{"Extra2"}},
+		},
+		ExternalDeps: map[string][]string{
+			"go": {"example.com/very/long/module/name/v2"},
+		},
+	}
+
+	var buf bytes.Buffer
+	Depgraph(&buf, project)
+	output := buf.String()
+
+	expectedSnippets := []string{
+		"Dependency Flow",
+		"Go: name",
+		"App",
+		"Core",
+		"main ──┬──▶ core/extra1/extra1",
+		"└──▶ core/root/root",
+		"root ───▶ core/mid/mid",
+		"HUBS: core/leaf/leaf (4←), core/mid/mid (2←)",
+		"6 files · 6 functions · 9 deps",
+	}
+
+	for _, snippet := range expectedSnippets {
+		if !strings.Contains(output, snippet) {
+			t.Fatalf("expected output to contain %q, got:\n%s", snippet, output)
+		}
+	}
+}