feat: LLM accuracy testing framework with 17-test catalog

Framework runs a category/subcategory test catalog against multiple
LLMs through an OpenAI-compatible endpoint. Deterministic evaluators
score each response. Reports render as table, markdown, or JSON.

cmd/llmtest/main_test.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/lukaszraczylo/llm-testbench/internal/report"
+)
+
+func TestSplitCSV(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		want []string
+	}{
+		{"single model", "uni/deepseek-v4-flash-0731", []string{"uni/deepseek-v4-flash-0731"}},
+		{"multiple models", "a,b,c", []string{"a", "b", "c"}},
+		{"trims whitespace around entries", " a , b ,c ", []string{"a", "b", "c"}},
+		{"drops empty entries from trailing comma", "a,b,", []string{"a", "b"}},
+		{"drops empty entries from doubled comma", "a,,b", []string{"a", "b"}},
+		{"empty string yields no entries", "", nil},
+		{"whitespace only yields no entries", "   ", nil},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := splitCSV(tt.in)
+			if len(got) != len(tt.want) {
+				t.Fatalf("splitCSV(%q) = %v, want %v", tt.in, got, tt.want)
+			}
+			for i := range got {
+				if got[i] != tt.want[i] {
+					t.Errorf("splitCSV(%q)[%d] = %q, want %q", tt.in, i, got[i], tt.want[i])
+				}
+			}
+		})
+	}
+}
+
+func TestValidateFormat(t *testing.T) {
+	tests := []struct {
+		name    string
+		in      string
+		want    report.Format
+		wantErr bool
+	}{
+		{"table", "table", report.FormatTable, false},
+		{"markdown", "markdown", report.FormatMarkdown, false},
+		{"json", "json", report.FormatJSON, false},
+		{"unknown format", "yaml", "", true},
+		{"empty format", "", "", true},
+		{"case sensitive: uppercase rejected", "TABLE", "", true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := validateFormat(tt.in)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("validateFormat(%q) error = %v, wantErr %v", tt.in, err, tt.wantErr)
+			}
+			if err == nil && got != tt.want {
+				t.Errorf("validateFormat(%q) = %q, want %q", tt.in, got, tt.want)
+			}
+		})
+	}
+}