lint: Check for README presence (and supporting commits)

cmd/lint.go

@@ -89,6 +89,10 @@ func lintTrack(path string) bool {
 			check: missingMetadata,
 			msg:   "An implementation for '%v' was found, but config.json does not reference this exercise.",
 		},
+		{
+			check: missingReadme,
+			msg:   "The implementation for '%v' is missing a README.",
+		},
 		{
 			check: missingSolution,
 			msg:   "The implementation for '%v' is missing an example solution.",
@@ -201,6 +205,25 @@ func missingSolution(t track.Track) []string {
 	return slugs
 }
 
+func missingReadme(t track.Track) []string {
+	readmes := map[string]bool{}
+	for _, exercise := range t.Exercises {
+		readmes[exercise.Slug] = exercise.HasReadme()
+	}
+	// Don't complain about missing readmes in foregone exercises.
+	for _, slug := range t.Config.ForegoneSlugs {
+		readmes[slug] = true
+	}
+
+	slugs := []string{}
+	for slug, ok := range readmes {
+		if !ok {
+			slugs = append(slugs, slug)
+		}
+	}
+	return slugs
+}
+
 func missingTestSuite(t track.Track) []string {
 	tests := map[string]bool{}
 	for _, exercise := range t.Exercises {

cmd/lint_test.go

@@ -45,6 +45,11 @@ func TestLintTrack(t *testing.T) {
 			path:     "../fixtures/broken-maintainers",
 			expected: true,
 		},
+		{
+			desc:     "should fail when given a track missing READMEs.",
+			path:     "../fixtures/missing-readme",
+			expected: true,
+		},
 		{
 			desc:     "should not fail when given a track with all of its bits in place.",
 			path:     "../fixtures/lint/valid-track",
@@ -110,6 +115,27 @@ func TestMissingMetadata(t *testing.T) {
 	assert.Equal(t, "cherry", slugs[1])
 }
 
+func TestMissingReadme(t *testing.T) {
+	track := track.Track{
+		Exercises: []track.Exercise{
+			{Slug: "apple"},
+			{Slug: "banana", ReadmePath: "README.md"},
+			{Slug: "cherry"},
+		},
+	}
+
+	slugs := missingReadme(track)
+
+	if len(slugs) != 2 {
+		t.Fatalf("Expected missing READMEs in 2 exercises, missing in %d", len(slugs))
+	}
+
+	sort.Strings(slugs)
+
+	assert.Equal(t, "apple", slugs[0])
+	assert.Equal(t, "cherry", slugs[1])
+}
+
 func TestMissingSolution(t *testing.T) {
 	track := track.Track{
 		Exercises: []track.Exercise{

fixtures/missing-readme/config.json

@@ -0,0 +1,14 @@
+{
+  "slug": "missing-readme",
+  "language": "Missing Readme",
+  "repository": "https://github.com/exercism/missing-readme",
+  "active": true,
+  "exercises": [
+    {
+      "uuid": "missingmissing",
+      "slug": "missing-readme",
+      "topics": [],
+      "difficulty": 1
+    }
+  ]
+}

track/exercise.go

@@ -11,6 +11,7 @@ import (
 // Exercise is an implementation of an Exercism exercise.
 type Exercise struct {
 	Slug          string
+	ReadmePath    string
 	SolutionPath  string
 	TestSuitePath string
 }
@@ -31,6 +32,11 @@ func NewExercise(root string, pg PatternGroup) (Exercise, error) {
 		return ex, err
 	}
 
+	err = setPath(root, "README\\.md", &ex.ReadmePath)
+	if err != nil {
+		return ex, err
+	}
+
 	return ex, err
 }
 
@@ -62,6 +68,11 @@ func setPath(root, pattern string, field *string) error {
 	return filepath.Walk(root, walkFn)
 }
 
+// HasReadme checks that an exercise has a README.
+func (ex Exercise) HasReadme() bool {
+	return ex.ReadmePath != ""
+}
+
 // HasTestSuite checks that an exercise has a test suite.
 func (ex Exercise) HasTestSuite() bool {
 	return ex.TestSuitePath != ""