From a30954ea71bb8498abaf127a8565d4fa226165cc Mon Sep 17 00:00:00 2001
From: Ville Vesilehto <ville@vesilehto.fi>
Date: Mon, 15 Sep 2025 20:17:35 +0300
Subject: [PATCH] test(view): improve test coverage (#7543)

Cover edge cases in config parser. Add rudimentary View/Filter
tests. Improves test coverage from 44% to 82%.

Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
---
 plugin/view/metadata_test.go | 22 +++++++++++
 plugin/view/setup_test.go    | 25 +++++++++++++
 plugin/view/view_test.go     | 71 ++++++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+)
 create mode 100644 plugin/view/metadata_test.go
 create mode 100644 plugin/view/view_test.go

diff --git a/plugin/view/metadata_test.go b/plugin/view/metadata_test.go
new file mode 100644
index 000000000..bd3cc13e6
--- /dev/null
+++ b/plugin/view/metadata_test.go
@@ -0,0 +1,22 @@
+package view
+
+import (
+	"context"
+	"testing"
+
+	"github.com/coredns/coredns/plugin/metadata"
+	"github.com/coredns/coredns/request"
+)
+
+func TestMetadata_PublishesViewName(t *testing.T) {
+	v := &View{viewName: "myview"}
+	ctx := metadata.ContextWithMetadata(context.Background())
+	st := request.Request{}
+	ctx = v.Metadata(ctx, st)
+
+	if f := metadata.ValueFunc(ctx, "view/name"); f == nil {
+		t.Fatalf("metadata value func is nil")
+	} else if got := f(); got != "myview" {
+		t.Fatalf("metadata value: got %q, want %q", got, "myview")
+	}
+}
diff --git a/plugin/view/setup_test.go b/plugin/view/setup_test.go
index 7c7838070..309d85cb8 100644
--- a/plugin/view/setup_test.go
+++ b/plugin/view/setup_test.go
@@ -1,9 +1,14 @@
 package view
 
 import (
+	"context"
+	"errors"
 	"testing"
 
 	"github.com/coredns/caddy"
+	ptest "github.com/coredns/coredns/plugin/test"
+
+	"github.com/miekg/dns"
 )
 
 func TestSetup(t *testing.T) {
@@ -17,6 +22,8 @@ func TestSetup(t *testing.T) {
 		{"view example {\n expr name() == 'example.com.'\n expr name() == 'example2.com.'\n}", false, 2},
 		{"view", true, 0},
 		{"view example {\n expr invalid expression\n}", true, 0},
+		{"view x {\n foo bar\n}\n", true, 0},
+		{"view a { }\nview b { }\n", true, 0},
 	}
 
 	for i, test := range tests {
@@ -36,3 +43,21 @@ func TestSetup(t *testing.T) {
 		}
 	}
 }
+
+func TestServeDNS_DelegatesToNext(t *testing.T) {
+	v := &View{}
+	wantCode := 123
+	wantErr := errors.New("boom")
+	v.Next = ptest.NextHandler(wantCode, wantErr)
+
+	rr := new(dns.Msg)
+	rr.SetQuestion("example.com.", dns.TypeA)
+	w := &ptest.ResponseWriter{}
+	gotCode, gotErr := v.ServeDNS(context.Background(), w, rr)
+	if gotCode != wantCode {
+		t.Fatalf("rcode: got %d, want %d", gotCode, wantCode)
+	}
+	if gotErr != wantErr {
+		t.Fatalf("error: got %v, want %v", gotErr, wantErr)
+	}
+}
diff --git a/plugin/view/view_test.go b/plugin/view/view_test.go
new file mode 100644
index 000000000..1f080cd11
--- /dev/null
+++ b/plugin/view/view_test.go
@@ -0,0 +1,71 @@
+package view
+
+import (
+	"context"
+	"testing"
+
+	"github.com/coredns/coredns/plugin/pkg/expression"
+	ptest "github.com/coredns/coredns/plugin/test"
+	"github.com/coredns/coredns/request"
+
+	"github.com/expr-lang/expr"
+	"github.com/expr-lang/expr/vm"
+	"github.com/miekg/dns"
+)
+
+func TestFilter_NoPrograms(t *testing.T) {
+	v := &View{viewName: "test"}
+	st := makeState(t, "example.com.")
+	if !v.Filter(context.Background(), st) {
+		t.Fatalf("expected true when no programs are configured")
+	}
+}
+
+func TestFilter_ErrorPaths(t *testing.T) {
+	st := makeState(t, "example.com.")
+
+	tests := []struct {
+		expr     string
+		expected bool
+	}{
+		{"name() == 'example.com.'", true},
+		{"name() == 'notexample.com.'", false},
+		{"1", false},
+		{"incidr('invalid', '1.2.3.0/24')", false},
+	}
+
+	for i, tc := range tests {
+		v := &View{progs: []*vm.Program{compileExpr(t, tc.expr)}}
+		got := v.Filter(context.Background(), st)
+		if got != tc.expected {
+			t.Fatalf("case %d expr %q: expected %v, got %v", i, tc.expr, tc.expected, got)
+		}
+	}
+}
+
+func TestView_Names(t *testing.T) {
+	v := &View{viewName: "v1"}
+	if v.ViewName() != "v1" {
+		t.Fatalf("ViewName() expected %q, got %q", "v1", v.ViewName())
+	}
+	if v.Name() != "view" {
+		t.Fatalf("Name() expected %q, got %q", "view", v.Name())
+	}
+}
+
+func compileExpr(t *testing.T, e string) *vm.Program {
+	t.Helper()
+	prog, err := expr.Compile(e, expr.Env(expression.DefaultEnv(context.Background(), nil)), expr.DisableBuiltin("type"))
+	if err != nil {
+		t.Fatalf("compile failed for %q: %v", e, err)
+	}
+	return prog
+}
+
+func makeState(t *testing.T, qname string) *request.Request {
+	t.Helper()
+	m := new(dns.Msg)
+	m.SetQuestion(dns.Fqdn(qname), dns.TypeA)
+	w := &ptest.ResponseWriter{}
+	return &request.Request{W: w, Req: m}
+}