add /emissions/year/{year} endpoint

README.md

@@ -13,8 +13,9 @@ The required raw data can be downloaded here https://www.kaggle.com/datasets/rej
 | List all countries                                | GET         | /countries                |
 | Returns a single country                          | GET         | /countries/{name}         |
 | List all emissions of all countries for each year | GET         | /emissions/year           |
+| Get all emissions of a specific year              | GET         | /emissions/year/{year}    |
 | List all emissions of all years for each country  | GET         | /emissions/country        |
-| List all emissions of a specific country          | GET         | /emissions/country/{name} |
+| Get all emissions of a specific country           | GET         | /emissions/country/{name} |
 
 ## 🚀 How to run
 

http-request-emissions.http

@@ -14,6 +14,18 @@
 # }
 GET {{url}}:{{port}}/emissions/year/
 
+### GET all emissions of a single year
+# expected response:
+# {
+#     "nox_emissions": {
+#         "average": 1597043.105081651,
+#         "median": 71152.08,
+#         "standard_deviation": 8007847.335584437
+#     },
+#     ...
+# }
+GET {{url}}:{{port}}/emissions/year/2000
+
 ### GET list of all emissions by year
 # expected response:
 # {

internal/resource/countries_test.go

@@ -17,15 +17,19 @@ type fakeCountryStorage struct {
 }
 
 func (s fakeCountryStorage) FindAllByYears() map[int][]*model.Emissions {
-	return nil
+	panic("not implemented")
+}
+
+func (s fakeCountryStorage) FindAllByYear(year int) map[string]*model.Emissions {
+	panic("not implemented")
 }
 
 func (s fakeCountryStorage) FindAllByCountries() map[string][]*model.Emissions {
-	return nil
+	panic("not implemented")
 }
 
 func (s fakeCountryStorage) FindAllByCountry(name string) map[int]*model.Emissions {
-	return nil
+	panic("not implemented")
 }
 
 func (s fakeCountryStorage) GetCountry(name string) *model.Country {

internal/resource/emissions.go

@@ -9,6 +9,7 @@ import (
 	"github.com/go-chi/render"
 	"github.com/montanaflynn/stats"
 	"net/http"
+	"strconv"
 )
 
 type EmissionResource struct {
@@ -86,6 +87,7 @@ func (rs EmissionResource) Routes() chi.Router {
 
 	r.Route("/year/", func(r chi.Router) {
 		r.Get("/", rs.ListByYear)
+		r.Get("/{year}", rs.GetByYear)
 	})
 
 	r.Route("/country/", func(r chi.Router) {
@@ -108,6 +110,26 @@ func (rs EmissionResource) ListByYear(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (rs EmissionResource) GetByYear(w http.ResponseWriter, r *http.Request) {
+	year, err := strconv.Atoi(chi.URLParam(r, "year"))
+	if err != nil {
+		if err := render.Render(w, r, ErrRender(fmt.Sprintf("Invalid year"), 400)); err != nil {
+			render.Status(r, 500)
+		}
+		return
+	}
+
+	var yearEmissions []*model.Emissions
+	for _, emissions := range rs.Storage.FindAllByYear(year) {
+		yearEmissions = append(yearEmissions, emissions)
+	}
+
+	response := newAirPollutionEmissionsResponse(yearEmissions)
+	if err := render.Render(w, r, response); err != nil {
+		render.Status(r, 500)
+	}
+}
+
 func (rs EmissionResource) ListByCountry(w http.ResponseWriter, r *http.Request) {
 	response := make(map[string]airPollutionEmissionsResponse)
 	for country, emissions := range rs.Storage.FindAllByCountries() {

internal/resource/emissions_test.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"strconv"
 	"testing"
 )
 
@@ -22,6 +23,14 @@ func (s fakeEmissionsStorage) FindAllByYears() map[int][]*model.Emissions {
 	return result
 }
 
+func (s fakeEmissionsStorage) FindAllByYear(year int) map[string]*model.Emissions {
+	result := make(map[string]*model.Emissions)
+	for i, e := range s.emissions {
+		result[strconv.Itoa(i)] = e
+	}
+	return result
+}
+
 func (s fakeEmissionsStorage) FindAllByCountries() map[string][]*model.Emissions {
 	result := make(map[string][]*model.Emissions)
 	result["test"] = s.emissions
@@ -37,11 +46,11 @@ func (s fakeEmissionsStorage) FindAllByCountry(name string) map[int]*model.Emiss
 }
 
 func (s fakeEmissionsStorage) GetCountry(name string) *model.Country {
-	return nil
+	panic("not implemented")
 }
 
 func (s fakeEmissionsStorage) GetCountries() []*model.Country {
-	return nil
+	panic("not implemented")
 }
 
 func TestEmissionsListByYear(t *testing.T) {
@@ -118,3 +127,32 @@ func TestEmissionsGetByCountry(t *testing.T) {
 	assert.Equal(t, 3.0, airPollutionEmissions.NOxEmissions.Median)
 	assert.Equal(t, 3.559026084010437, airPollutionEmissions.NOxEmissions.StandardDeviation)
 }
+
+func TestEmissionsGetByYear(t *testing.T) {
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	ctx := chi.NewRouteContext()
+	req = req.WithContext(context.WithValue(req.Context(), chi.RouteCtxKey, ctx))
+	ctx.URLParams.Add("year", "666")
+	emissionsHandler := EmissionResource{Storage: fakeEmissionsStorage{[]*model.Emissions{{
+		NOxEmissions: 10,
+	}, {
+		NOxEmissions: 2,
+	}, {
+		NOxEmissions: 3,
+	}}}}
+
+	emissionsHandler.GetByYear(w, req)
+	res := w.Result()
+	defer res.Body.Close()
+	data, err := ioutil.ReadAll(res.Body)
+	assert.Nil(t, err)
+	assert.Equal(t, 200, res.StatusCode)
+
+	airPollutionEmissions := airPollutionEmissionsResponse{}
+	err = json.Unmarshal(data, &airPollutionEmissions)
+	assert.Nil(t, err)
+	assert.Equal(t, 5.0, airPollutionEmissions.NOxEmissions.Average)
+	assert.Equal(t, 3.0, airPollutionEmissions.NOxEmissions.Median)
+	assert.Equal(t, 3.559026084010437, airPollutionEmissions.NOxEmissions.StandardDeviation)
+}

internal/store/storage.go

@@ -13,6 +13,7 @@ type Store struct {
 
 type Storage interface {
 	FindAllByYears() map[int][]*model.Emissions
+	FindAllByYear(year int) map[string]*model.Emissions
 	FindAllByCountries() map[string][]*model.Emissions
 	FindAllByCountry(name string) map[int]*model.Emissions
 	GetCountry(name string) *model.Country
@@ -97,6 +98,17 @@ func (s *Store) FindAllByYears() map[int][]*model.Emissions {
 	return emissions
 }
 
+func (s *Store) FindAllByYear(year int) map[string]*model.Emissions {
+	emissions := make(map[string]*model.Emissions)
+	for name, countryEmissions := range s.emissions {
+		countryEmissionsOfYear, found := countryEmissions[year]
+		if found {
+			emissions[name] = &countryEmissionsOfYear
+		}
+	}
+	return emissions
+}
+
 func (s *Store) FindAllByCountries() map[string][]*model.Emissions {
 	emissions := make(map[string][]*model.Emissions)
 	for name, countryEmissions := range s.emissions {