caddyhttp: Fix default SNI for default conn policy (#3141)

* add integration tests

* removed SNI test

* remove integration test condition

* minor edit

* fix sni when using static certificates

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

caddytest/integration/caddyfile_test.go

@@ -0,0 +1,91 @@
+package integration
+
+import (
+	"testing"
+
+	"github.com/caddyserver/caddy/v2/caddytest"
+)
+
+func TestRespond(t *testing.T) {
+
+	// arrange
+	caddytest.InitServer(t, ` 
+  {
+    http_port     9080
+    https_port    9443
+  }
+  
+  localhost:9080 {
+    respond /version 200 {
+      body "hello from a.caddy.localhost"
+    }	
+    }
+  `, "caddyfile")
+
+	// act and assert
+	caddytest.AssertGetResponse(t, "http://localhost:9080/version", 200, "hello from a.caddy.localhost")
+}
+
+func TestRedirect(t *testing.T) {
+
+	// arrange
+	caddytest.InitServer(t, `
+  {
+    http_port     9080
+    https_port    9443
+  }
+  
+  localhost:9080 {
+    
+    redir / http://localhost:9080/hello 301
+    
+    respond /hello 200 {
+      body "hello from b"
+    }	
+    }
+  `, "caddyfile")
+
+	// act and assert
+	caddytest.AssertRedirect(t, "http://localhost:9080/", "http://localhost:9080/hello", 301)
+
+	// follow redirect
+	caddytest.AssertGetResponse(t, "http://localhost:9080/", 200, "hello from b")
+}
+
+func TestDuplicateHosts(t *testing.T) {
+
+	// act and assert
+	caddytest.AssertLoadError(t,
+		`
+    localhost:9080 {
+    }
+  
+    localhost:9080 { 
+    }
+    `,
+		"caddyfile",
+		"duplicate site address not allowed")
+}
+
+func TestDefaultSNI(t *testing.T) {
+
+	// arrange
+	caddytest.InitServer(t, ` 
+  {
+    http_port     9080
+    https_port    9443
+    default_sni   *.caddy.localhost
+  }
+  
+  127.0.0.1:9443 {
+    tls /caddy.localhost.crt /caddy.localhost.key {
+    }
+    respond /version 200 {
+      body "hello from a.caddy.localhost"
+    }	
+  }
+  `, "caddyfile")
+
+	// act and assert
+	caddytest.AssertGetResponse(t, "https://127.0.0.1:9443/version", 200, "hello from a.caddy.localhost")
+}