diff --git a/internal/configuration/configuration_test.go b/internal/configuration/configuration_test.go
index b77bd02a..cb2586ef 100644
--- a/internal/configuration/configuration_test.go
+++ b/internal/configuration/configuration_test.go
@@ -118,7 +118,7 @@ func TestConfiguration(t *testing.T) {
 			for key, wanted := range tc.wantedConfig {
 				got := Get[any](key)
 				if got != wanted {
-					t.Errorf(cmp.Diff(got, wanted))
+					t.Errorf("%s", cmp.Diff(got, wanted))
 				}
 			}
 			viper.Reset()
@@ -159,7 +159,7 @@ func TestConfigPaths(t *testing.T) {
 		got := defaultConfigPaths()
 
 		if !cmp.Equal(got, want) {
-			t.Errorf(cmp.Diff(got, want))
+			t.Errorf("%s", cmp.Diff(got, want))
 		}
 	})
 
@@ -189,7 +189,7 @@ func TestConfigPaths(t *testing.T) {
 		got := defaultConfigPaths()
 
 		if !cmp.Equal(got, want) {
-			t.Errorf(cmp.Diff(got, want))
+			t.Errorf("%s", cmp.Diff(got, want))
 		}
 	})
 
@@ -225,7 +225,7 @@ func TestConfigPaths(t *testing.T) {
 		got := defaultConfigPaths()
 
 		if !cmp.Equal(got, want) {
-			t.Errorf(cmp.Diff(got, want))
+			t.Errorf("%s", cmp.Diff(got, want))
 		}
 	})
 }
diff --git a/internal/coverage/coverage_test.go b/internal/coverage/coverage_test.go
index 03e4a8e8..07756299 100644
--- a/internal/coverage/coverage_test.go
+++ b/internal/coverage/coverage_test.go
@@ -104,10 +104,10 @@ func TestCoverageRun(t *testing.T) {
 			secondGot := fmt.Sprintf("go %v", strings.Join(holder.events[1].args, " "))
 
 			if !cmp.Equal(firstGot, firstWant) {
-				t.Errorf(cmp.Diff(firstGot, firstWant))
+				t.Errorf("%s", cmp.Diff(firstGot, firstWant))
 			}
 			if !cmp.Equal(secondGot, secondWant) {
-				t.Errorf(cmp.Diff(secondGot, secondWant))
+				t.Errorf("%s", cmp.Diff(secondGot, secondWant))
 			}
 		})
 	}
diff --git a/internal/engine/executor_test.go b/internal/engine/executor_test.go
index 4f5f615c..e5a1c674 100644
--- a/internal/engine/executor_test.go
+++ b/internal/engine/executor_test.go
@@ -312,7 +312,7 @@ func TestMutatorRun(t *testing.T) {
 			got := fmt.Sprintf("go %v", strings.Join(holder.args, " "))
 
 			if !cmp.Equal(got, want) {
-				t.Errorf(fmt.Sprintf("\n+ %s\n- %s\n", got, want))
+				t.Errorf("\n+ %s\n- %s\n", got, want)
 			}
 
 			timeoutDifference := absTimeDiff(holder.timeout, expectedTimeout*2)
diff --git a/internal/engine/tokenmutator_test.go b/internal/engine/tokenmutator_test.go
index f2eeb65c..bd209049 100644
--- a/internal/engine/tokenmutator_test.go
+++ b/internal/engine/tokenmutator_test.go
@@ -80,7 +80,7 @@ func TestMutantApplyAndRollback(t *testing.T) {
 			t.Fatal(err)
 		}
 		if !cmp.Equal(string(got), want[i]) {
-			t.Fatalf(cmp.Diff(want[i], string(got)))
+			t.Errorf("%s", cmp.Diff(want[i], string(got)))
 		}
 
 		err = mut.Rollback()
@@ -93,7 +93,7 @@ func TestMutantApplyAndRollback(t *testing.T) {
 			t.Fatal(err)
 		}
 		if !cmp.Equal(string(got), rollbackWant) {
-			t.Fatalf(cmp.Diff(rollbackWant, string(got)))
+			t.Errorf("%s", cmp.Diff(rollbackWant, string(got)))
 		}
 	}
 }
diff --git a/internal/engine/workdir/workdir_test.go b/internal/engine/workdir/workdir_test.go
index d3745097..d5173b32 100644
--- a/internal/engine/workdir/workdir_test.go
+++ b/internal/engine/workdir/workdir_test.go
@@ -80,7 +80,7 @@ func checkForDifferentFile(t *testing.T, srcDir string, dstDir string) func(path
 			t.Errorf("expected Name to be %v, got %v", srcFileInfo.Name(), dstFileInfo.Name())
 		}
 		if !cmp.Equal(dstFileInfo.Mode(), srcFileInfo.Mode()) {
-			t.Errorf(cmp.Diff(srcFileInfo.Mode(), dstFileInfo.Mode()))
+			t.Errorf("%s", cmp.Diff(srcFileInfo.Mode(), dstFileInfo.Mode()))
 		}
 
 		return nil
diff --git a/internal/mutator/mutator_test.go b/internal/mutator/mutator_test.go
index 397b0ef5..419ee4cd 100644
--- a/internal/mutator/mutator_test.go
+++ b/internal/mutator/mutator_test.go
@@ -65,7 +65,7 @@ func TestStatusString(t *testing.T) {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			if tc.mutationStatus.String() != tc.expected {
-				t.Errorf(cmp.Diff(tc.mutationStatus.String(), tc.expected))
+				t.Errorf("%s", cmp.Diff(tc.mutationStatus.String(), tc.expected))
 			}
 		})
 	}
@@ -137,7 +137,7 @@ func TestTypeString(t *testing.T) {
 		tc := tc
 		t.Run(tc.name, func(t *testing.T) {
 			if tc.mutantType.String() != tc.expected {
-				t.Errorf(cmp.Diff(tc.mutantType.String(), tc.expected))
+				t.Errorf("%s", cmp.Diff(tc.mutantType.String(), tc.expected))
 			}
 		})
 	}
diff --git a/internal/report/logger_test.go b/internal/report/logger_test.go
index 8fe632a1..aa673564 100644
--- a/internal/report/logger_test.go
+++ b/internal/report/logger_test.go
@@ -102,6 +102,6 @@ func TestLogger(t *testing.T) {
 		"       LIVED CONDITIONALS_BOUNDARY at aFolder/aFile.go:12:3\n"
 
 	if !cmp.Equal(got, want) {
-		t.Errorf(cmp.Diff(got, want))
+		t.Errorf("%s", cmp.Diff(got, want))
 	}
 }
diff --git a/internal/report/report.go b/internal/report/report.go
index 3a709a10..12a81c99 100644
--- a/internal/report/report.go
+++ b/internal/report/report.go
@@ -233,14 +233,14 @@ func (r *reportStatus) assess(tEfficacy, rCoverage float64) error {
 	if et == 0 {
 		et = float64(configuration.Get[int](configuration.UnleashThresholdEfficacyKey))
 	}
-	if et > 0 && tEfficacy <= et {
+	if et > 0 && tEfficacy < et {
 		return execution.NewExitErr(execution.EfficacyThreshold)
 	}
 	ct := configuration.Get[float64](configuration.UnleashThresholdMCoverageKey)
 	if ct == 0 {
 		ct = float64(configuration.Get[int](configuration.UnleashThresholdMCoverageKey))
 	}
-	if ct > 0 && rCoverage <= ct {
+	if ct > 0 && rCoverage < ct {
 		return execution.NewExitErr(execution.MutantCoverageThreshold)
 	}
 
diff --git a/internal/report/report_test.go b/internal/report/report_test.go
index 18f1ab56..e4afb10e 100644
--- a/internal/report/report_test.go
+++ b/internal/report/report_test.go
@@ -32,13 +32,13 @@ import (
 	"github.com/hectane/go-acl"
 	"github.com/spf13/viper"
 
+	"github.com/go-gremlins/gremlins/internal/execution"
 	"github.com/go-gremlins/gremlins/internal/log"
 	"github.com/go-gremlins/gremlins/internal/mutator"
 	"github.com/go-gremlins/gremlins/internal/report"
 	"github.com/go-gremlins/gremlins/internal/report/internal"
 
 	"github.com/go-gremlins/gremlins/internal/configuration"
-	"github.com/go-gremlins/gremlins/internal/execution"
 )
 
 var fakePosition = newPosition("aFolder/aFile.go", 3, 12)
@@ -122,7 +122,7 @@ func TestReport(t *testing.T) {
 			got := out.String()
 
 			if !cmp.Equal(got, tc.want) {
-				t.Errorf(cmp.Diff(tc.want, got))
+				t.Errorf("%s", cmp.Diff(tc.want, got))
 			}
 		})
 	}
@@ -176,7 +176,7 @@ func TestReport(t *testing.T) {
 			got := out.String()
 
 			if !cmp.Equal(got, tc.want) {
-				t.Errorf(cmp.Diff(tc.want, got))
+				t.Errorf("%s", cmp.Diff(tc.want, got))
 			}
 		})
 	}
@@ -275,19 +275,20 @@ func TestAssessment(t *testing.T) {
 
 			err := report.Do(data)
 
-			if tc.expectError && err == nil {
-				t.Fatal("expected an error")
-			}
-			if !tc.expectError {
-				return
-			}
-			var exitErr *execution.ExitError
-			if errors.As(err, &exitErr) {
-				if exitErr.ExitCode() == 0 {
-					t.Errorf("expected exit code to be different from 0, got %d", exitErr.ExitCode())
+			if tc.expectError {
+				if err == nil {
+					t.Fatal("expected an error")
+				}
+				var exitErr *execution.ExitError
+				if errors.As(err, &exitErr) {
+					if exitErr.ExitCode() == 0 {
+						t.Errorf("expected exit code to be different from 0, got %d", exitErr.ExitCode())
+					}
+				} else {
+					t.Errorf("expected err to be ExitError")
 				}
-			} else {
-				t.Errorf("expected err to be ExitError")
+			} else if err != nil {
+				t.Fatal("unexpected error")
 			}
 		})
 	}
@@ -326,7 +327,7 @@ func TestMutantLog(t *testing.T) {
 		"     SKIPPED CONDITIONALS_BOUNDARY at aFolder/aFile.go:12:3\n"
 
 	if !cmp.Equal(got, want) {
-		t.Errorf(cmp.Diff(got, want))
+		t.Errorf("%s", cmp.Diff(got, want))
 	}
 }
 
@@ -377,7 +378,7 @@ func TestReportToFile(t *testing.T) {
 		}
 
 		if !cmp.Equal(got, want, cmpopts.SortSlices(sortOutputFile), cmpopts.SortSlices(sortMutation)) {
-			t.Errorf(cmp.Diff(got, want))
+			t.Errorf("%s", cmp.Diff(got, want))
 		}
 	})