pkgs/misc: add RemoveDuplicates function (MR 22)

pkgs/misc/misc.go

@@ -56,3 +56,23 @@ func Merge(a map[string]string, b map[string]string) {
 		a[k] = v
 	}
 }
+
+// Removes duplicate entries from the given string slice and returns a slice
+// with the unique values
+func RemoveDuplicates(in []string) (out []string) {
+	// use a map to "remove" duplicates. the value in the map is totally
+	// irrelevant
+	outMap := make(map[string]bool)
+	for _, s := range in {
+		if ok := outMap[s]; !ok {
+			outMap[s] = true
+		}
+	}
+
+	out = make([]string, 0, len(outMap))
+	for k := range outMap {
+		out = append(out, k)
+	}
+
+	return
+}

pkgs/misc/misc_test.go

@@ -5,6 +5,7 @@ package misc
 
 import (
 	"reflect"
+	"sort"
 	"testing"
 )
 
@@ -69,3 +70,56 @@ func TestMerge(t *testing.T) {
 		})
 	}
 }
+
+func TestRemoveDuplicates(t *testing.T) {
+	subtests := []struct {
+		name     string
+		in       []string
+		expected []string
+	}{
+		{
+			name: "no duplicates",
+			in: []string{
+				"foo",
+				"bar",
+				"banana",
+				"airplane",
+			},
+			expected: []string{
+				"foo",
+				"bar",
+				"banana",
+				"airplane",
+			},
+		},
+		{
+			name: "all duplicates",
+			in: []string{
+				"foo",
+				"foo",
+				"foo",
+				"foo",
+			},
+			expected: []string{
+				"foo",
+			},
+		},
+		{
+			name:     "empty",
+			in:       []string{},
+			expected: []string{},
+		},
+	}
+
+	for _, st := range subtests {
+		t.Run(st.name, func(t *testing.T) {
+			// note: sorting to make comparison easier later
+			sort.Strings(st.expected)
+			out := RemoveDuplicates(st.in)
+			sort.Strings(out)
+			if !reflect.DeepEqual(st.expected, out) {
+				t.Fatalf("expected: %q, got: %q\n", st.expected, out)
+			}
+		})
+	}
+}