feat: Initial version

main_test.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"testing"
+)
+
+func TestRun(t *testing.T) {
+	// Test cases for Run Tests
+	testCases := []struct {
+		name   string
+		col    int
+		op     string
+		exp    string
+		files  []string
+		expErr error
+	}{
+		{name: "RunAvg1File", col: 3, op: "avg", exp: "227.6\n",
+			files:  []string{"./testdata/example.csv"},
+			expErr: nil,
+		},
+		{name: "RunAvgMultiFiles", col: 3, op: "avg", exp: "233.84\n",
+			files:  []string{"./testdata/example.csv", "./testdata/example2.csv"},
+			expErr: nil,
+		},
+		{name: "RunFailRead", col: 2, op: "avg", exp: "",
+			files:  []string{"./testdata/example.csv", "./testdata/fakefile.csv"},
+			expErr: os.ErrNotExist,
+		}, {name: "RunFailColumn", col: 0, op: "avg", exp: "",
+			files:  []string{"./testdata/example.csv"},
+			expErr: ErrInvalidColumn,
+		},
+		{name: "RunFailNoFiles", col: 2, op: "avg", exp: "",
+			files:  []string{},
+			expErr: ErrNoFiles,
+		},
+		{name: "RunFailOperation", col: 2, op: "invalid", exp: "",
+			files:  []string{"./testdata/example.csv"},
+			expErr: ErrInvalidOperation,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			var res bytes.Buffer
+			err := run(tc.files, tc.op, tc.col, &res)
+
+			if tc.expErr != nil {
+				if err == nil {
+					t.Errorf("Expected error. Got nil instead")
+				}
+				if !errors.Is(err, tc.expErr) {
+					t.Errorf("Expected error %q, got %q instead", tc.expErr, err)
+				}
+				return
+			}
+			if err != nil {
+				t.Errorf("Unexpected error: %q", err)
+			}
+			if res.String() != tc.exp {
+				t.Errorf("Expected %q, got %q instead", tc.exp, &res)
+			}
+		})
+	}
+}