Add exemplar and tests

exercises/concept/bird-watcher/.docs/instructions.md

@@ -8,7 +8,7 @@ Usually you use a tally in a notebook to count the birds, but to better work wit
 Let us start analyzing the data by getting a high level view.
 Find out how many birds you counted in total since you started your logs.
 
-Implement a function `TotalBirdCount` that accepts an array that contains the bird count per day.
+Implement a function `TotalBirdCount` that accepts an slice that contains the bird count per day.
 It should return the total number of birds that you counted.
 
 ```go

exercises/concept/bird-watcher/.meta/config.json

@@ -1,11 +1,23 @@
 {
-  "blurb": "Professionalize counting the birds in your garden with for loops.",
-  "authors": ["sachinmk27"],
-  "contributors": [],
+  "blurb": "Count the birds in your garden with for loops.",
+  "authors": [
+    "sachinmk27"
+  ],
+  "contributors": [
+    "andrerfcsantos"
+  ],
   "files": {
-    "solution": ["bird_watcher.go"],
-    "test": ["bird_watcher_test.go"],
-    "exemplar": [".meta/exemplar.go"]
+    "solution": [
+      "bird_watcher.go"
+    ],
+    "test": [
+      "bird_watcher_test.go"
+    ],
+    "exemplar": [
+      ".meta/exemplar.go"
+    ]
   },
-  "forked_from": ["javascript/bird-watcher"]
-}
+  "forked_from": [
+    "javascript/bird-watcher"
+  ]
+}

exercises/concept/bird-watcher/.meta/exemplar.go

@@ -0,0 +1,32 @@
+package birdwatcher
+
+// TotalBirdCount return the total bird count by summing
+// the individual day's counts
+func TotalBirdCount(birdsPerDay []int) int {
+	count := 0
+	for i := 0; i < len(birdsPerDay); i++ {
+		count += birdsPerDay[i]
+	}
+	return count
+}
+
+// BirdsInWeek returns the total bird count by summing
+// only the items belonging to the given week
+func BirdsInWeek(birdsPerDay []int, week int) int {
+	count := 0
+	startOfWeek := (week - 1) * 7
+	endOfWeek := startOfWeek + 7
+	for i := startOfWeek; i < endOfWeek; i++ {
+		count += birdsPerDay[i]
+	}
+	return count
+}
+
+// FixBirdCountLog returns the bird counts after correcting
+// the bird counts for alternate days
+func FixBirdCountLog(birdsPerDay []int) []int {
+	for i := 0; i < len(birdsPerDay); i += 2 {
+		birdsPerDay[i] = birdsPerDay[i] + 1
+	}
+	return birdsPerDay
+}

exercises/concept/bird-watcher/bird_watcher.go

@@ -8,7 +8,7 @@ func TotalBirdCount(birdsPerDay []int) int {
 
 // BirdsInWeek returns the total bird count by summing
 // only the items belonging to the given week
-func BirdsInWeek(birdsPerDay []int) int {
+func BirdsInWeek(birdsPerDay []int, week int) int {
 	panic("Please implement the BirdsInWeek() function")
 }
 

exercises/concept/bird-watcher/bird_watcher_test.go

@@ -0,0 +1,121 @@
+package birdwatcher
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestTotalBirdCount(t *testing.T) {
+	tests := []struct {
+		name       string
+		birdCounts []int
+		want       int
+	}{
+		{
+			name:       "calculates the correct total number of birds",
+			birdCounts: []int{9, 0, 8, 4, 5, 1, 3},
+			want:       30,
+		},
+		{
+			name:       "works for a short bird count list",
+			birdCounts: []int{2},
+			want:       2,
+		},
+		{
+			name:       "works for a long bird count list",
+			birdCounts: []int{2, 8, 4, 1, 3, 5, 0, 4, 1, 6, 0, 3, 0, 1, 5, 4, 1, 1, 2, 6},
+			want:       57,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := TotalBirdCount(tt.birdCounts); got != tt.want {
+				t.Errorf("TotalBirdCount(%v) = %v; want %v", tt.birdCounts, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestBirdsInWeek(t *testing.T) {
+	tests := []struct {
+		name       string
+		birdCounts []int
+		week       int
+		want       int
+	}{
+		{
+			name:       "calculates the number of birds in the first week",
+			birdCounts: []int{3, 0, 5, 1, 0, 4, 1, 0, 3, 4, 3, 0, 8, 0},
+			week:       1,
+			want:       14,
+		},
+		{
+			name:       "calculates the number of birds for a week in the middle of the log",
+			birdCounts: []int{4, 7, 3, 2, 1, 1, 2, 0, 2, 3, 2, 7, 1, 3, 0, 6, 5, 3, 7, 2, 3},
+			week:       2,
+			want:       18,
+		},
+		{
+			name:       "works when there is only one week",
+			birdCounts: []int{3, 0, 3, 3, 2, 1, 0},
+			week:       1,
+			want:       12,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := BirdsInWeek(tt.birdCounts, tt.week); got != tt.want {
+				t.Errorf("BirdsInWeek(%v) = %v; want %v", tt.birdCounts, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFixBirdCount(t *testing.T) {
+	tests := []struct {
+		name       string
+		birdCounts []int
+		week       int
+		want       []int
+	}{
+		{
+			name:       "returns a bird count list with the corrected values",
+			birdCounts: []int{3, 0, 5, 1, 0, 4, 1, 0, 3, 4, 3, 0},
+			want:       []int{4, 0, 6, 1, 1, 4, 2, 0, 4, 4, 4, 0},
+		},
+		{
+			name:       "works for a short bird count list",
+			birdCounts: []int{4, 2},
+			want:       []int{5, 2},
+		},
+		{
+			name:       "works for a long bird count list",
+			birdCounts: []int{2, 8, 4, 1, 3, 5, 0, 4, 1, 6, 0, 3, 0, 1, 5, 4, 1, 1, 2, 6},
+			want:       []int{3, 8, 5, 1, 4, 5, 1, 4, 2, 6, 1, 3, 1, 1, 6, 4, 2, 1, 3, 6},
+		},
+		{
+			name:       "does not create new slice",
+			birdCounts: []int{3, 0, 5, 1, 0, 4, 1, 0, 3, 4, 3, 0},
+			want:       []int{4, 0, 6, 1, 1, 4, 2, 0, 4, 4, 4, 0},
+		},
+	}
+
+	// Test normal cases - last test needs to be tested differently
+	for _, tt := range tests[:len(tests)-1] {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := FixBirdCountLog(tt.birdCounts); !reflect.DeepEqual(tt.want, got) {
+				t.Errorf("FixBirdCountLog(%v) = %v; want %v", tt.birdCounts, got, tt.want)
+			}
+		})
+	}
+
+	// Test special case
+	t.Run("does not create new slice", func(t *testing.T) {
+		tt := tests[len(tests)-1]
+		got := FixBirdCountLog(tt.birdCounts)
+		if reflect.ValueOf(got).Pointer() != reflect.ValueOf(tt.birdCounts).Pointer() {
+			t.Error("it looks like that you are creating a new slice in the function FixBirdCountLog - " +
+				"please make sure you are modifying the slice passed as argument")
+		}
+	})
+}

exercises/concept/bird-watcher/go.mod

@@ -1,3 +1,3 @@
 module birdwatcher
 
-go 1.13
+go 1.14