test(coverage): add unit tests across all packages; remove dead code

- Added comprehensive table-driven test suites for all packages:
  cmd/glint, cicontext, fetcher, graph, linter, model, resolver.
  Coverage reaches 98%+ statement coverage across the codebase.
- Replaced os.Exit calls in cmd/glint with an `exit` variable so tests
  can capture exit codes without terminating the test process.
- Removed unreachable code found during coverage analysis:
  dead guard in cicontext.parseRegexLiteral; dead len(jobs)==0 branch
  in graph.Pipeline; skipWin struct field and dead continue in
  graph.convertToPNG; pipelineSVG return type simplified to string.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/cicontext/reachability_more_test.go

@@ -0,0 +1,262 @@
+package cicontext
+
+import (
+	"testing"
+
+	"git.k3nny.fr/glint/internal/model"
+)
+
+// ── JobState.String ───────────────────────────────────────────────────────────
+
+func TestJobStateString(t *testing.T) {
+	if JobActive.String() != "active" { t.Errorf("active: got %q", JobActive.String()) }
+	if JobManual.String() != "manual" { t.Errorf("manual: got %q", JobManual.String()) }
+	if JobSkipped.String() != "skipped" { t.Errorf("skipped: got %q", JobSkipped.String()) }
+}
+
+// ── whenToState ───────────────────────────────────────────────────────────────
+
+func TestWhenToState(t *testing.T) {
+	cases := []struct { when string; want JobState }{
+		{"never",      JobSkipped},
+		{"manual",     JobManual},
+		{"on_success", JobActive},
+		{"always",     JobActive},
+		{"",           JobActive},
+	}
+	for _, tc := range cases {
+		got := whenToState(tc.when)
+		if got != tc.want {
+			t.Errorf("whenToState(%q)=%v want %v", tc.when, got, tc.want)
+		}
+	}
+}
+
+// ── EvalJob: only/except paths ────────────────────────────────────────────────
+
+func TestEvalJob_OnlyExcept(t *testing.T) {
+	ctx := New("main", "", "", nil)
+
+	t.Run("only branches matches", func(t *testing.T) {
+		job := model.Job{Only: []any{"branches"}}
+		if EvalJob(job, ctx) != JobActive {
+			t.Error("expected active on branch")
+		}
+	})
+
+	t.Run("only tags excludes branch push", func(t *testing.T) {
+		job := model.Job{Only: []any{"tags"}}
+		if EvalJob(job, ctx) != JobSkipped {
+			t.Error("expected skipped — we are on a branch, not tag")
+		}
+	})
+
+	t.Run("except branches skips on branch push", func(t *testing.T) {
+		job := model.Job{Script: "echo ok", Except: []any{"branches"}}
+		if EvalJob(job, ctx) != JobSkipped {
+			t.Error("expected skipped — branches excluded")
+		}
+	})
+
+	t.Run("except non-matching source does not skip", func(t *testing.T) {
+		job := model.Job{Except: []any{"schedules"}}
+		if EvalJob(job, ctx) != JobActive {
+			t.Error("expected active — schedule is not the source")
+		}
+	})
+
+	t.Run("job when: manual with no filter", func(t *testing.T) {
+		job := model.Job{When: "manual"}
+		if EvalJob(job, ctx) != JobManual {
+			t.Error("expected manual")
+		}
+	})
+
+	t.Run("empty context returns active", func(t *testing.T) {
+		emptyCtx := New("", "", "", nil)
+		job := model.Job{Only: []any{"tags"}}
+		if EvalJob(job, emptyCtx) != JobActive {
+			t.Error("empty context should always return active")
+		}
+	})
+}
+
+// ── EvalJob: rules path ───────────────────────────────────────────────────────
+
+func TestEvalJob_Rules(t *testing.T) {
+	ctx := New("main", "", "", nil)
+
+	t.Run("rule with never when excludes", func(t *testing.T) {
+		job := model.Job{Rules: []model.Rule{{When: "never"}}}
+		if EvalJob(job, ctx) != JobSkipped {
+			t.Error("expected skipped — when:never")
+		}
+	})
+
+	t.Run("no matching rule → skipped", func(t *testing.T) {
+		job := model.Job{Rules: []model.Rule{
+			{If: "$CI_COMMIT_BRANCH == \"develop\"", When: "on_success"},
+		}}
+		if EvalJob(job, ctx) != JobSkipped {
+			t.Error("expected skipped — no rule matches main branch with develop condition")
+		}
+	})
+}
+
+// ── onlyMatches / exceptMatches ───────────────────────────────────────────────
+
+func TestOnlyMatches(t *testing.T) {
+	branchCtx := New("main", "", "", nil)
+	tagCtx    := New("", "v1.0", "", nil)
+	mrCtx     := New("", "", "merge_request_event", nil)
+
+	cases := []struct {
+		name string
+		only any
+		ctx  *Context
+		want bool
+	}{
+		{"nil only always matches", nil, branchCtx, true},
+		{"unrecognised form permissive", 42, branchCtx, true},
+		{"string form — branches keyword", "branches", branchCtx, true},
+		{"string form — tags keyword miss", "tags", branchCtx, false},
+		{"slice — merge_requests keyword", []any{"merge_requests"}, mrCtx, true},
+		{"slice — schedules keyword", []any{"schedules"}, branchCtx, false},
+		{"slice — pipelines keyword", []any{"pipelines"}, New("","","pipeline",nil), true},
+		{"slice — pushes keyword", []any{"pushes"}, New("","","push",nil), true},
+		{"slice — web keyword", []any{"web"}, New("","","web",nil), true},
+		{"slice — api keyword", []any{"api"}, New("","","api",nil), true},
+		{"slice — tag keyword match", []any{"tags"}, tagCtx, true},
+		{"glob pattern matches", []any{"feat/*"}, New("feat/abc","","",nil), true},
+		{"glob no match", []any{"feat/*"}, branchCtx, false},
+		{"regex pattern matches branch", []any{"/^main.*/"}, branchCtx, true},
+		{"regex pattern no match", []any{"/^develop/"}, branchCtx, false},
+		{"invalid regex treated as glob", []any{"/[invalid/"}, branchCtx, false},
+		{"map form with refs key", map[string]any{"refs": []any{"branches"}}, branchCtx, true},
+		{"map form no refs — permissive", map[string]any{"variables": []any{}}, branchCtx, true},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := onlyMatches(tc.only, tc.ctx)
+			if got != tc.want {
+				t.Errorf("onlyMatches: got %v want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestExceptMatches(t *testing.T) {
+	branchCtx := New("main", "", "", nil)
+
+	cases := []struct {
+		name   string
+		except any
+		want   bool
+	}{
+		{"nil except never excludes", nil, false},
+		{"unrecognised form not excluded", 42, false},
+		{"branches excludes on branch push", []any{"branches"}, true},
+		{"tags does not exclude branch push", []any{"tags"}, false},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := exceptMatches(tc.except, branchCtx)
+			if got != tc.want {
+				t.Errorf("exceptMatches: got %v want %v", got, tc.want)
+			}
+		})
+	}
+}
+
+// ── extractRefList ────────────────────────────────────────────────────────────
+
+func TestExtractRefList(t *testing.T) {
+	cases := []struct {
+		name  string
+		input any
+		wantN int // -1 means nil expected
+	}{
+		{"string", "branches", 1},
+		{"slice of strings", []any{"a", "b", "c"}, 3},
+		{"slice with non-string items skipped", []any{"a", 42, "b"}, 2},
+		{"map with refs key", map[string]any{"refs": []any{"branches"}}, 1},
+		{"map without refs key returns nil", map[string]any{"variables": nil}, -1},
+		{"unknown type returns nil", 123, -1},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := extractRefList(tc.input)
+			if tc.wantN == -1 {
+				if got != nil { t.Errorf("expected nil, got %v", got) }
+			} else {
+				if len(got) != tc.wantN { t.Errorf("len: got %d want %d (%v)", len(got), tc.wantN, got) }
+			}
+		})
+	}
+}
+
+// ── globMatches / matchGlob ───────────────────────────────────────────────────
+
+func TestGlobMatches(t *testing.T) {
+	cases := []struct {
+		pattern string
+		s       string
+		want    bool
+	}{
+		{"main", "main", true},
+		{"main", "develop", false},
+		{"feat/*", "feat/abc", true},
+		{"feat/*", "feat/", true},
+		{"feat/*", "main", false},
+		{"*", "anything", true},
+		{"*", "", true},
+		{"prefix*suffix", "prefixMIDDLEsuffix", true},
+		{"prefix*suffix", "prefixsuffix", true},
+		{"prefix*suffix", "prefixNO", false},
+		{"a*b*c", "aXbYc", true},
+		{"a*b*c", "abc", true},
+	}
+	for _, tc := range cases {
+		t.Run(tc.pattern+"/"+tc.s, func(t *testing.T) {
+			got := globMatches(tc.pattern, tc.s)
+			if got != tc.want {
+				t.Errorf("globMatches(%q, %q)=%v want %v", tc.pattern, tc.s, got, tc.want)
+			}
+		})
+	}
+}
+
+// ── refPatternMatches ─────────────────────────────────────────────────────────
+
+func TestRefPatternMatches(t *testing.T) {
+	cases := []struct {
+		pattern string
+		ref     string
+		want    bool
+	}{
+		{"/^main$/", "main", true},
+		{"/^main$/", "develop", false},
+		{"/feature/", "feature/abc", true},
+		{"feat/*", "feat/x", true},
+		{"main", "main", true},
+		{"main", "develop", false},
+		{"", "main", false},    // empty ref for pattern with no wildcard
+	}
+	for _, tc := range cases {
+		t.Run(tc.pattern+"@"+tc.ref, func(t *testing.T) {
+			got := refPatternMatches(tc.pattern, tc.ref)
+			if got != tc.want {
+				t.Errorf("refPatternMatches(%q, %q)=%v want %v", tc.pattern, tc.ref, got, tc.want)
+			}
+		})
+	}
+}
+
+// TestRefListMatches_Schedule verifies the "schedules" keyword matches when
+// CI_PIPELINE_SOURCE is "schedule".
+func TestRefListMatches_Schedule(t *testing.T) {
+	ctx := New("", "", "schedule", nil)
+	if !refListMatches([]string{"schedules"}, ctx) {
+		t.Error("schedules keyword should match when source is 'schedule'")
+	}
+}