1 files changed, 175 insertions, 0 deletions
diff --git a/internal/parser/csv_test.go b/internal/parser/csv_test.go
new file mode 100644
index 0000000..ffe9034
--- /dev/null
+++ b/internal/parser/csv_test.go
@@ -0,0 +1,175 @@
+package parser
+
+import (
+	"context"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestCSVParser_Parse(t *testing.T) {
+	tests := []struct {
+		name      string
+		input     string
+		wantCount int
+		wantErr   bool
+	}{
+		{
+			name:      "valid single line",
+			input:     `test_metric,env=prod;host=server1,42.5,1234567890000`,
+			wantCount: 1,
+			wantErr:   false,
+		},
+		{
+			name: "multiple lines",
+			input: `metric1,label1=value1,100,1234567890000
+metric2,label2=value2,200,1234567891000
+metric3,label3=value3,300,1234567892000`,
+			wantCount: 3,
+			wantErr:   false,
+		},
+		{
+			name: "with comments",
+			input: `# This is a comment
+metric1,env=test,50,1234567890000
+# Another comment
+metric2,env=prod,75,1234567891000`,
+			wantCount: 2,
+			wantErr:   false,
+		},
+		{
+			name:      "no timestamp defaults to now",
+			input:     `metric1,env=test,100`,
+			wantCount: 1,
+			wantErr:   false,
+		},
+		{
+			name:      "no labels",
+			input:     `metric1,,100,1234567890000`,
+			wantCount: 1,
+			wantErr:   false,
+		},
+		{
+			name:      "empty input",
+			input:     "",
+			wantCount: 0,
+			wantErr:   false,
+		},
+		{
+			name: "invalid line causes error",
+			input: `metric1,env=test,100,1234567890000
+invalid
+metric2,env=prod,200,1234567891000`,
+			wantCount: 0,
+			wantErr:   true,
+		},
+		{
+			name: "invalid value skipped",
+			input: `metric1,env=test,not_a_number,1234567890000
+metric2,env=prod,200,1234567891000`,
+			wantCount: 1,
+			wantErr:   false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			parser := NewCSVParser()
+			reader := strings.NewReader(tt.input)
+			ctx := context.Background()
+
+			samples, err := parser.Parse(ctx, reader)
+
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Parse() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if len(samples) != tt.wantCount {
+				t.Errorf("Parse() returned %d samples, want %d", len(samples), tt.wantCount)
+			}
+		})
+	}
+}
+
+func TestCSVParser_ParseLabels(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		want  map[string]string
+	}{
+		{
+			name:  "single label",
+			input: "env=prod",
+			want:  map[string]string{"env": "prod"},
+		},
+		{
+			name:  "multiple labels",
+			input: "env=prod;host=server1;region=us-west",
+			want:  map[string]string{"env": "prod", "host": "server1", "region": "us-west"},
+		},
+		{
+			name:  "empty string",
+			input: "",
+			want:  map[string]string{},
+		},
+		{
+			name:  "invalid label format skipped",
+			input: "env=prod;invalid;host=server1",
+			want:  map[string]string{"env": "prod", "host": "server1"},
+		},
+		{
+			name:  "with spaces",
+			input: " env = prod ; host = server1 ",
+			want:  map[string]string{"env": "prod", "host": "server1"},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := parseLabels(tt.input)
+			if len(got) != len(tt.want) {
+				t.Errorf("parseLabels() returned %d labels, want %d", len(got), len(tt.want))
+			}
+			for k, v := range tt.want {
+				if got[k] != v {
+					t.Errorf("parseLabels()[%s] = %v, want %v", k, got[k], v)
+				}
+			}
+		})
+	}
+}
+
+func TestCSVParser_ParseWithContext(t *testing.T) {
+	t.Run("context cancellation", func(t *testing.T) {
+		parser := NewCSVParser()
+		ctx, cancel := context.WithCancel(context.Background())
+		cancel() // Cancel immediately
+
+		input := strings.NewReader(`metric1,env=test,100,1234567890000`)
+		_, err := parser.Parse(ctx, input)
+
+		if err != context.Canceled {
+			t.Errorf("Expected context.Canceled error, got %v", err)
+		}
+	})
+}
+
+func TestCSVParser_ParseTimestamp(t *testing.T) {
+	parser := NewCSVParser()
+	input := `metric1,env=test,100,1234567890000`
+	reader := strings.NewReader(input)
+	ctx := context.Background()
+
+	samples, err := parser.Parse(ctx, reader)
+	if err != nil {
+		t.Fatalf("Parse() error = %v", err)
+	}
+	if len(samples) != 1 {
+		t.Fatalf("Expected 1 sample, got %d", len(samples))
+	}
+
+	expectedTime := time.UnixMilli(1234567890000)
+	if !samples[0].Timestamp.Equal(expectedTime) {
+		t.Errorf("Timestamp = %v, want %v", samples[0].Timestamp, expectedTime)
+	}
+}