Added strings set to package

.gitlab-ci.yml

+image: golang
+cache:
+  paths:
+    - go/
+
+variables:
+  GOPATH: "$CI_PROJECT_DIR/go"
+  GOCACHE: "$CI_PROJECT_DIR/go/cache"
+  GOPROXY: "https://proxy.golang.org"
+
+test:
+  script:
+    - go test --cover ./...
\ No newline at end of file

doc.go

+// Common is a collection of common packages that are shared between projects.
+//
+// This allows for cleaner code usage within Eckler and also reduces dependency
+// bloat when using external dependencies.
+package common

go.mod

+module gitlab.fs.eckler.ca/life-2/common
+
+go 1.12
+
+require github.com/stretchr/testify v1.3.0

go.sum

+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

sets/strings.go

+package sets
+
+//Strings represents a set of strings
+type Strings struct {
+	data map[string]bool
+}
+
+//NewStrings initializes a new set of strings
+func NewStrings(initialValues ...string) *Strings {
+	data := make(map[string]bool)
+	for _, v := range initialValues {
+		data[v] = true
+	}
+	return &Strings{
+		data: data,
+	}
+}
+
+//Add will add one or more values to the set
+func (ss *Strings) Add(values ...string) {
+	for _, v := range values {
+		ss.data[v] = true
+	}
+}
+
+//Cardinality will return the number of unique elements in the set
+func (ss *Strings) Cardinality() int {
+	return len(ss.data)
+}
+
+//Contains will determine if the string provided exists in the set
+func (ss *Strings) Contains(value string) bool {
+	v, ok := ss.data[value]
+	return ok && v
+}
+
+//Intersect will return a new set with only the values found in both sets
+func (ss *Strings) Intersect(ss2 *Strings) *Strings {
+	src, dest := ss, ss2
+	if len(ss.data) > len(ss2.data) {
+		src, dest = ss2, ss
+	}
+	results := make(map[string]bool)
+	for v := range src.data {
+		if dest.Contains(v) {
+			results[v] = true
+		}
+	}
+	return &Strings{
+		data: results,
+	}
+}

sets/strings_test.go

+package sets
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestStrings(t *testing.T) {
+	s := NewStrings()
+	s.Add("A")
+	s.Add("B")
+
+	require.Equal(t, 2, s.Cardinality())
+	require.True(t, s.Contains("B"))
+	require.False(t, s.Contains("C"))
+
+	s2 := NewStrings()
+	s2.Add("B")
+	s2.Add("C")
+
+	s3 := s.Intersect(s2)
+	require.Equal(t, 1, s3.Cardinality())
+	require.True(t, s3.Contains("B"))
+	require.False(t, s3.Contains("A"))
+	require.False(t, s3.Contains("C"))
+}