diff --git a/.gitignore b/.gitignore
index 22d2d00b..5f549c3a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ src/config/config.go
 .vscode
 vendor/
 dbclones/
+coverage.out
diff --git a/src/hmnurl/hmnurl_test.go b/src/hmnurl/hmnurl_test.go
index 0652494b..b7c778d4 100644
--- a/src/hmnurl/hmnurl_test.go
+++ b/src/hmnurl/hmnurl_test.go
@@ -35,6 +35,14 @@ func TestProjectIndex(t *testing.T) {
 	AssertRegexMatch(t, BuildProjectIndex(), RegexProjectIndex, nil)
 }
 
+func TestShowcase(t *testing.T) {
+	AssertRegexMatch(t, BuildShowcase(), RegexShowcase, nil)
+}
+
+func TestStreams(t *testing.T) {
+	AssertRegexMatch(t, BuildStreams(), RegexStreams, nil)
+}
+
 func TestSiteMap(t *testing.T) {
 	AssertRegexMatch(t, BuildSiteMap(), RegexSiteMap, nil)
 }
@@ -79,6 +87,13 @@ func TestFeed(t *testing.T) {
 	assert.Panics(t, func() { BuildFeedWithPage(0) })
 }
 
+func TestPodcast(t *testing.T) {
+	AssertRegexMatch(t, BuildPodcast(""), RegexPodcast, nil)
+	AssertSubdomain(t, BuildPodcast(""), "")
+	AssertSubdomain(t, BuildPodcast("hmn"), "")
+	AssertSubdomain(t, BuildPodcast("hero"), "hero")
+}
+
 func TestForumCategory(t *testing.T) {
 	AssertRegexMatch(t, BuildForumCategory("", nil, 1), RegexForumCategory, nil)
 	AssertRegexMatch(t, BuildForumCategory("", []string{"wip"}, 2), RegexForumCategory, map[string]string{"cats": "wip", "page": "2"})
@@ -329,6 +344,8 @@ func TestMarkRead(t *testing.T) {
 }
 
 func AssertSubdomain(t *testing.T, fullUrl string, expectedSubdomain string) {
+	t.Helper()
+
 	parsed, err := url.Parse(fullUrl)
 	ok := assert.Nilf(t, err, "Full url could not be parsed: %s", fullUrl)
 	if !ok {
@@ -344,6 +361,8 @@ func AssertSubdomain(t *testing.T, fullUrl string, expectedSubdomain string) {
 }
 
 func AssertRegexMatch(t *testing.T, fullUrl string, regex *regexp.Regexp, paramsToVerify map[string]string) {
+	t.Helper()
+
 	parsed, err := url.Parse(fullUrl)
 	ok := assert.Nilf(t, err, "Full url could not be parsed: %s", fullUrl)
 	if !ok {
@@ -378,6 +397,8 @@ func AssertRegexMatch(t *testing.T, fullUrl string, regex *regexp.Regexp, params
 }
 
 func AssertRegexNoMatch(t *testing.T, fullUrl string, regex *regexp.Regexp) {
+	t.Helper()
+
 	parsed, err := url.Parse(fullUrl)
 	ok := assert.Nilf(t, err, "Full url could not be parsed: %s", fullUrl)
 	if !ok {
diff --git a/src/hmnurl/test/coverage_test.go b/src/hmnurl/test/coverage_test.go
new file mode 100644
index 00000000..dc6069d9
--- /dev/null
+++ b/src/hmnurl/test/coverage_test.go
@@ -0,0 +1,84 @@
+package test
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+	"testing"
+
+	"git.handmade.network/hmn/hmn/src/ansicolor"
+	"github.com/stretchr/testify/assert"
+)
+
+/*
+We have these tests in a separate package so that we can run the hmnurl package tests without
+recursively invoking ourselves.
+*/
+
+// Test that all hmnurl functions starting with Build are covered by tests.
+func TestRouteCoverage(t *testing.T) {
+	tmp := t.TempDir()
+	covFilePath := filepath.Join(tmp, "coverage.out")
+
+	outputAndAssert(t, exec.Command("go", "test", "./..", "-coverprofile="+covFilePath), "failed to run hmnurl tests")
+	coverageOutput := outputAndAssert(t, exec.Command("go", "tool", "cover", "-func="+covFilePath), "failed to run coverage tool")
+
+	coverLineRe := regexp.MustCompile("(?P<name>\\w+)\\t+(?P<percent>[\\d.]+)%$")
+	var uncoveredBuildFuncs []string
+	for i, line := range bytes.Split(coverageOutput, []byte("\n")) {
+		line := string(line)
+		if line == "" || strings.HasPrefix(line, "total") {
+			continue
+		}
+
+		matches := coverLineRe.FindStringSubmatch(line)
+		if matches == nil {
+			panic(fmt.Sprintf("line %d of coverage data could not be parsed (\"%s\")", i+1, line))
+		}
+
+		funcName := matches[coverLineRe.SubexpIndex("name")]
+		coverPercentStr := matches[coverLineRe.SubexpIndex("percent")]
+
+		if strings.HasPrefix(funcName, "Build") {
+			coverPercent, err := strconv.ParseFloat(coverPercentStr, 64)
+			if err != nil {
+				panic(err)
+			}
+
+			if coverPercent == 0 {
+				uncoveredBuildFuncs = append(uncoveredBuildFuncs, funcName)
+			}
+		}
+	}
+
+	if len(uncoveredBuildFuncs) > 0 {
+		t.Logf("The following url Build functions were not covered by tests:\n")
+		for _, funcName := range uncoveredBuildFuncs {
+			t.Logf("%s\n", funcName)
+		}
+		t.FailNow()
+	}
+}
+
+func outputAndAssert(t *testing.T, cmd *exec.Cmd, args ...interface{}) []byte {
+	t.Helper()
+
+	var stdout bytes.Buffer
+	cmd.Stdout = io.MultiWriter(os.Stdout, &stdout)
+	cmd.Stderr = os.Stderr
+
+	fmt.Println(ansicolor.Gray + ansicolor.Italic + cmd.String() + ansicolor.Reset)
+
+	fmt.Print(ansicolor.Gray)
+	err := cmd.Run()
+	fmt.Print(ansicolor.Reset)
+	assert.Nil(t, err, args...)
+
+	return stdout.Bytes()
+}
diff --git a/src/hmnurl/urls.go b/src/hmnurl/urls.go
index 7786a7ac..869b644a 100644
--- a/src/hmnurl/urls.go
+++ b/src/hmnurl/urls.go
@@ -9,6 +9,11 @@ import (
 	"git.handmade.network/hmn/hmn/src/oops"
 )
 
+/*
+Any function in this package whose name starts with Build is required to be covered by a test.
+This helps ensure that we don't generate URLs that can't be routed.
+*/
+
 // TODO(asaf): Make this whole file only crash in Dev
 
 var RegexHomepage = regexp.MustCompile("^/$")
@@ -51,6 +56,8 @@ func BuildAtomFeed() string {
 	return Url("/atom", nil)
 }
 
+// QUESTION(ben): Can we change these routes?
+
 var RegexLoginAction = regexp.MustCompile("^/login$")
 
 func BuildLoginAction(redirectTo string) string {
@@ -163,7 +170,7 @@ func BuildPodcast(projectSlug string) string {
  */
 
 // TODO(asaf): This also matches urls generated by BuildForumThread (/t/ is identified as a cat, and the threadid as a page)
-// This shouldn't be a problem since we will match Thread before Category in the router, but should be enforce it here?
+// This shouldn't be a problem since we will match Thread before Category in the router, but should we enforce it here?
 var RegexForumCategory = regexp.MustCompile(`^/forums(/(?P<cats>[^\d/]+(/[^\d]+)*))?(/(?P<page>\d+))?$`)
 
 func BuildForumCategory(projectSlug string, subforums []string, page int) string {