Add numeronyms functionality

Implemented numeronym functionality in a executable Go program which
returns a slice of numeronyms given an input of n strings

Closes Lab 04 (#419)

04_numeronym/patrickmarabeas/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+var out io.Writer = os.Stdout
+
+// Convert string to a numeronym
+func generateNumeronym(s string) string {
+	length := len(s)
+	// Early bailout if string is less than 4 characters
+	if length < 4 {
+		return s
+	}
+	// Format as "{unicode character}{decimal}{unicode character}"
+	return fmt.Sprintf("%c%d%c", s[0], length-2, s[length-1])
+}
+
+// Convert n strings into a slice of numeronyms
+func numeronyms(vals ...string) []string {
+	result := make([]string, len(vals))
+	i := 0
+	for _, numeronym := range vals {
+		result[i] = generateNumeronym(numeronym)
+		i++
+	}
+
+	return result
+}
+
+func main() {
+	fmt.Fprintln(out, numeronyms("accessibility", "Kubernetes", "abc"))
+}

04_numeronym/patrickmarabeas/main_test.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+func TestMainOutput(t *testing.T) {
+	var buf bytes.Buffer
+	out = &buf
+
+	main()
+
+	expected := fmt.Sprintf("%s\n", "[a11y K8s abc]")
+	got := buf.String()
+
+	t.Run("Main function", func(t *testing.T) {
+		if expected != got {
+			t.Errorf("\nExpected: %s\nGot:      %s", expected, got)
+		}
+	})
+}
+
+func TestGenerateNumeronym(t *testing.T) {
+	var cases = map[string]struct {
+		input    string
+		expected string
+	}{
+		"Lowercase": {
+			input:    "lowercase",
+			expected: "l7e",
+		},
+		"Uppercase": {
+			input:    "Uppercase",
+			expected: "U7e",
+		},
+		"Three letters": {
+			input:    "abc",
+			expected: "abc",
+		},
+		"Two letters": {
+			input:    "ab",
+			expected: "ab",
+		},
+		"Single letter": {
+			input:    "a",
+			expected: "a",
+		},
+		"Empty": {
+			input:    "",
+			expected: "",
+		},
+	}
+
+	for name, c := range cases {
+		got, expected := generateNumeronym(c.input), c.expected
+		t.Run(name, func(t *testing.T) {
+			if got != expected {
+				t.Errorf("\nExpected: %s\nGot:      %s", expected, got)
+			}
+		})
+	}
+}
+
+func TestNumeronyms(t *testing.T) {
+	test := numeronyms("lowercase", "Uppercase")
+	expected := []string{"l7e", "U7e"}
+
+	for i, got := range test {
+		// Lint error: Using the variable on range scope `got` / `i` in function literal
+		i := i
+		got := got
+		t.Run(fmt.Sprintf("String of index %d", i), func(t *testing.T) {
+			if got != expected[i] {
+				t.Errorf("\nExpected: %s\nGot:      %s", expected[i], got)
+			}
+		})
+	}
+}