feat: add filter on price range

WIP

Signed-off-by: Julien Riou <julien@riou.xyz>

filter_range_test.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestRangeFilter(t *testing.T) {
+	tests := []struct {
+		name     string  // product name
+		price    float64 // product price
+		model    string  // model regex to apply on the product name
+		min      float64 // minimum price
+		max      float64 // maximum price
+		included bool    // should be included or not
+	}{
+		{"MSI GeForce RTX 3090 GAMING X", 99.99, "3090", 50.0, 100.0, true},   // model match and price is in the range, should be included
+		{"MSI GeForce RTX 3090 GAMING X", 99.99, "3080", 50.0, 100.0, true},   // model doesn't match, should be included
+		{"MSI GeForce RTX 3090 GAMING X", 999.99, "3090", 50.0, 100.0, false}, // model match and price is outside of the range, shoud not be included
+		{"MSI GeForce RTX 3090 GAMING X", 99.99, "", 50.0, 100.0, true},       // model regex is missing, should be included
+	}
+
+	for i, tc := range tests {
+		t.Run(fmt.Sprintf("TestRangeFilter#%d", i), func(t *testing.T) {
+			product := &Product{Name: tc.name, Price: tc.price}
+			filter, err := NewRangeFilter(tc.model, tc.min, tc.max)
+			if err != nil {
+				t.Errorf("cannot create filter with model regex '%s' and price range [%.2f, %.2f]: %s", tc.model, tc.min, tc.max, err)
+			}
+
+			included := filter.Include(product)
+
+			if included != tc.included {
+				t.Errorf("product '%s' with model regex '%s' and range [%.2f, %.2f]: got included=%t, want included=%t", tc.name, tc.model, tc.min, tc.max, included, tc.included)
+			} else {
+				if included {
+					t.Logf("product '%s' included by model regex '%s' and range [%.2f, %.2f]", tc.name, tc.model, tc.min, tc.max)
+				} else {
+					t.Logf("product '%s' excluded by model regex '%s' and range [%.2f, %.2f]", tc.name, tc.model, tc.min, tc.max)
+				}
+			}
+
+		})
+	}
+}